Small Moths Flying Around House: Effective Solutions to Enjoy a Bug-Free Home

Having small moths flying around your house can be quite a nuisance. These tiny, winged insects might make you feel like your home is no longer the clean and comfortable space you once knew. While it’s normal to see a few moths indoors from time to time, a sudden increase in their numbers may indicate a larger issue at hand.

One type of small moth that is commonly found indoors is the moth fly, also known as the drain fly. These insects can be found in damp environments like sinks and floor drains, and they resemble tiny moths due to their fuzzy appearance. It’s important to identify the type of moth you’re dealing with, their breeding sites, and take proper measures to prevent their growth.

Besides the moth fly, there are over 160,000 species of moth worldwide, with 11,000 of them residing in the United States. Different species may require different intervention methods, so being aware of the common household moth pests can help you tackle the problem more effectively. Don’t worry, with a little persistence and the right approach, you can reclaim your space and keep these pesky moths at bay.

Understanding the Moth Problem

Moths can be a nuisance in your home, especially if they infest your clothing and food. They’re attracted to certain materials like wool, fur, cotton, and silk, making your closets a potential target. Two common species that might infest your home are the webbing clothes moth and the case-bearing clothes moth.

If you notice small, brown house moths flying around, it’s a sign that your home may have a moth problem. Keep an eye out for other signs like holes in clothes and damaged fabrics.

Here are some common moth species you might encounter in your house:

• Webbing Clothes Moth: Feeds on wool, fur, and other natural fibers
• Case-Bearing Clothes Moth: Also feeds on natural fibers, but creates a case or cocoon to protect itself
• Brown House Moth: Prefers a diverse habitat, including stored food products

To deal with a moth infestation, it’s essential to identify the species and understand their preferred habitat. This will help you effectively control and prevent future infestations.

Types of Household Moths

Pantry Moth

Also known as the Indian meal moth, these moths infest food items in your kitchen. They are attracted to grains, cereals, and pet food. For example,

• They have a wingspan of about 16-20mm.
• Pantry moths lay eggs in food items that lead to larvae.

You can avoid pantry moths by storing food in airtight containers and keeping your kitchen clean.

Clothes Moth

There are a few different types of clothes moths, such as the common clothes moth, webbing clothes moth, and case-bearing clothes moth.

Common Clothes Moth

• This moth has a wingspan of 12-15mm.
• The larvae feed on wool, silk, and other organic materials.

Webbing Clothes Moth

• Slightly smaller than the common clothes moth with a wingspan of 10-12mm.
• Larvae spin webs on infested items, making them more noticeable.

Case-Bearing Clothes Moth

• Smaller than webbing clothes moth, with a wingspan of 9-12mm.
• The larvae create a silken case around themselves as they feed on fabrics.

The best way to prevent clothes moths is to keep your clothes clean, well-ventilated, and occasionally inspect them for signs of infestation.

Brown House Moth

The brown house moth is another common household pest. Some of their features include:

• A wingspan of about 15-26mm.
• They are dark brown with a few lighter markings.

Larvae of brown house moths feed on various materials, including natural fibers and even stored products. To prevent their infestation, maintain cleanliness around your home and use mothballs in storage areas.

Life Cycle of Moths

Moths go through various life stages. These stages consist of eggs, larvae, pupae, and finally, adult moths. Let’s explore each stage in more detail.

Eggs: Female moths lay their eggs on suitable host plants. The number of eggs laid depends on the species. Be cautious, as some people can have allergic reactions to these eggs.

Larvae: After hatching, moth larvae, often called caterpillars, emerge. These caterpillars feed on the host plant and grow larger over time. They may produce silk or webbing, which some species use to create shelters.

Pupae: Once fully grown, caterpillars enter the pupal stage, where they transform into adult moths. This metamorphosis occurs within a cocoon, spun from silk produced by the caterpillar. The pupal stage can vary in length, mainly depending on temperature.

Adult Moths: After completing their metamorphosis, moths emerge as adults, ready to mate and repeat the cycle.

As a homeowner, you may encounter moth larvae and adult moths flying around your house. Keep in mind that their presence can cause a few issues; some caterpillars can cause damage to plants, while others may leave behind allergenic substances.

Why Are Moths Attracted to Your Home?

Moths are often attracted to your home due to a variety of reasons. One common factor is the presence of light sources within your house, mainly at night. Moths tend to get disoriented and drawn towards artificial lights like your porch or indoor lights.

Another significant reason is their search for food and nesting places. These insects can infest your closets, fabric storage areas, and other spaces containing items they can munch on. Some moths like the clothes moth feed primarily on natural fibers, while others like the Indian meal moth target dried food items in your pantry, such as:

• Dried fruit
• Flour
• Cereals
• Grains
• Nuts
• Seeds

Moth infestations can also occur when moths search for nectar from indoor plants and flowers. They can easily be lured by the sweet scent of nectar or overripe fruits like pears in your kitchen.

To help reduce the chances of a moth infestation, consider the following steps to protect your home:

• Seal off any cracks and crevices around your house.
• Store dried food items in airtight containers.
• Regularly clean your pantry to prevent the accumulation of crumbs and spilled food particles.
• Wash and store clothes in sealed bags, particularly those made of natural fibers.
• Use mothballs or other moth deterrents in your storage and closet spaces.
• Turn off unnecessary lights at night or use less attractive yellow or amber light sources.

By following these precautions, you can help make your home less enticing for moths and avoid dealing with pesky infestations.

Damage Caused by Moths

Moths can cause considerable damage to a variety of items in your home. Some of the most common materials affected by these insects include:

• Wool
• Fur
• Clothes
• Grains
• Cereals
• Flour
• Nuts
• Beans
• Tea
• Pasta
• Bread
• Dried food
• Fabrics
• Textiles

Moth larvae are the primary culprits behind the damage, as they feed on these materials to grow and develop.

When it comes to your wardrobe, moths can ruin your favorite wool or fur garments. They tend to munch on the natural fibers, creating small holes and weakening the fabric’s structure.

Moths can also wreak havoc in your pantry. They are known for infesting grains, cereals, and other staple foods. For example, they might infest a bag of flour, leaving behind a visible webbing and contaminating the contents.

In addition to the physical damage, some people may experience an allergic reaction to moth larvae or the tiny scales shed by adult moths. This can manifest as skin irritation, respiratory issues, or aggravated asthma symptoms.

To avoid damage caused by moths, consider taking preventative measures such as:

• Storing clothes in sealed containers or garment bags
• Regularly cleaning your pantry and checking for signs of infestation
• Maintaining a clean and well-organized living space
• Using natural remedies like lavender or cedar to repel moths

By being proactive about moth prevention, you can protect your belongings and maintain a moth-free home.

Prevention and Control Measures

To prevent and control a moth infestation, you need to adopt various strategies. One effective method is maintaining a clean environment. Regularly clean your home, including vacuuming floors, washing fabrics, and wiping surfaces to remove moth eggs and larvae.

Moth traps can help in controlling the infestation. Place pheromone moth traps that attract adult moths, reducing their population and breeding opportunities. Remember to change traps as needed.

For items prone to moth infestations, consider using airtight containers. Storing clothes, food, and other susceptible items in sealed containers will keep moths out.

Using extreme temperatures can also help. If possible, put infested items in the freezer for a few days to kill moth eggs and larvae. Likewise, washing items in hot water or using heating techniques can be effective.

Prevention measures include the use of natural deterrents, such as cedar and essential oils. Cedar contains oils that repel moths, making it an ideal choice for wardrobe and storage spaces. You can also dab essential oils, like lavender or peppermint, on cotton balls and place them around your home.

Lastly, consider using insecticides for severe infestations. Apply an approved indoor insecticide to affected areas, ensuring proper ventilation and safety precautions. Monitor the temperature, as some insecticides work best under specific conditions.

Remember, implementing a combination of these control measures and maintaining a clean home will prevent small moths from flying around your house.

Treating Moth Infestation

To effectively treat a moth infestation in your home, it’s essential to first identify the type of moth. For instance, clothes moths are often found in closets and bedrooms, while drain or moth flies are typically found near sinks and drains.

Once you’ve identified the type of moth, consider implementing various pest control methods. One option is using moth traps, which can effectively catch adult moths. Some traps use pheromones to lure moths, while others use sticky surfaces or ultraviolet light.

Another crucial aspect of treating infestations is cleaning. Thoroughly clean the affected areas, including vacuuming carpets, washing clothing and linens, and dry cleaning items that cannot be washed. This process helps remove moth larvae and eggs, preventing future infestations.

Remember that clothing storage is vital in preventing clothes moth infestations. Make sure you:

• Store clothing in airtight containers or garment bags
• Ensure items are clean before storing them
• Regularly inspect stored items for signs of moths

Using essential oils can be a natural and effective way to deter moths. For example, lavender and rosemary are known to repel moths. You can add a few drops of essential oil to cotton balls and place them in closets, drawers, and storage containers.

For more heavy-duty treatments, consider using insecticides that are formulated specifically for moths. Keep in mind that some chemicals can damage fabrics and are toxic to humans or pets, so follow the manufacturer’s instructions carefully and exercise caution.

Lastly, check your home – especially basements and areas prone to mold growth – for conditions that may attract moths. Address any issues such as dampness or mold to discourage moths from lingering in these spaces.

By taking these steps and regularly monitoring your home, you can successfully treat moth infestations and prevent them from recurring in the future.

Food and Fabric Storage Practices

To avoid attracting small moths like pantry moths and flour moths, it’s essential to properly store your food. Items commonly affected by these pests include grains, cereals, flour, nuts, dried fruit, beans, tea, pasta, bread, dried food, and spices.

A good storage practice is using airtight containers for your food. This helps to protect your dry goods from infestation. Some examples of suitable containers are glass jars, plastic containers with tight-fitting lids, metal canisters, or resealable plastic bags.

It’s important to keep your pantry at the right temperature. Pantry moths thrive in warm environments, so try to maintain a cooler temperature in your storage areas. Storing certain items, like nuts and seeds, in the freezer is another effective method for preventing moth infestations.

When it comes to fabric storage, be sure to clean and properly package items like clothing, linens, and bedding before storing them. Moths are attracted to fibers containing natural oils, so regular laundering is essential. Vacuum your storage spaces regularly to remove any loose fibers or larvae.

Here is a comparison table for different storage methods:

In conclusion, implementing proper food and fabric storage practices is essential for keeping small moths out of your house and protecting your belongings from damage.

After Treatment Measures

Keeping your home moth-free doesn’t end with pest control treatment. Let’s check out some after-treatment measures you can implement to avoid future moth infestations.

Cleaning regularly is essential. Vacuum all areas, including corners and behind furniture. For example, regularly cleaning your basements can reduce moth habitat.

Store food in airtight containers. This blocks access for moths to their potential food sources. Consider investing in airtight containers for items like grains, cereals, or pet food.

For linen and clothing, try using moth traps. They contain pheromones that attract and capture adult moths, disrupting their lifecycle.

When it comes to plants, check them for signs of moth activity. Inspect them for ants too, as they can sometimes indicate moth presence.

Be mindful of odors, as certain smells can attract moths. Regularly air your house to maintain a fresh environment.

Cleaning vs. Food Storage

Here’s a summary of prevention measures to keep in mind:

• Regularly clean all areas of your home
• Store food in airtight containers
• Use moth traps for linen and clothing storage
• Check plants for moth activity and ants
• Keep your home well-ventilated to prevent odorous attraction

Similar Pests

When dealing with small moths flying around your house, it’s essential to understand that there are other similar pests you may encounter, such as ants and butterflies.

Ants are common household pests that can become a nuisance. They are social insects and live in colonies. Here are some key features of ants:

• Small in size, ranging from 1/16 to 1/2 inch long
• Typically found in the kitchen searching for food
• Can be red, brown, or black in color

Ants are attracted to sweet and greasy food, so keeping your kitchen clean and storing food in sealed containers can help prevent an infestation. While ants may not seem as bothersome as moths, they can contaminate food and cause structural damage to your home.

Butterflies, on the other hand, are usually harmless and aesthetically pleasing to many. However, they can sometimes be mistaken for moths. Some distinguishing characteristics include:

• Present during the daytime, while moths are primarily nocturnal
• Generally bright and colorful wings
• Wings are held vertically when at rest, unlike moths that usually hold their wings flat

While butterflies are typically not considered pests, caterpillars – the larval stage of butterflies and moths – can cause damage to your garden by feeding on the leaves of plants.

Here’s a comparison table to help you differentiate between moths, ants, and butterflies:

By recognizing these similar pests, you can take proper actions to keep your home free of unwanted visitors.

Conclusion

In the end, dealing with small moths flying around your house can be a nuisance. Here are some key points to remember:

• Identify the type of moth: Knowing the species of moths in your home can help you address the issue effectively.
• Locate their source: Find where these moths are breeding, such as drain flies that breed in pipes and drains.
• Control methods: Implement both chemical and non-chemical ways to manage the infestation and prevent future occurrences.

As a result, by understanding the moth situation in your house and taking appropriate steps, you can create a healthier and cleaner living space. Remember, the key is to act quickly and decisively to tackle the issue head-on. Good luck!

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Mysterious Encased Grublike Thing

What the heck?
Location: South Dakota kitchen floor
May 18, 2011 8:34 am
I found this on the floor. At first I thought it was something off a sunflower but found this worm looking thing inside.
Signature: Please help

We are baffled as to how to even categorize this thing.  There are not enough visible characteristics except to say that it resembles a grub or maggot, but being in that casing is quite curious.  Furthermore, why are there two of them?  The casing looks fibrous and hemplike, or possibly like fur.  Do you perhaps have a house pet with similar looking hair?  We are going to feature your photo in the hopes that our readership is able to provide some information.

Karl solves the Mystery
Mysterious Encased Grublike Thing – May 18, 2011
Hi Daniel and Please help:
Your mysterious objects look to me like the mature, presumably overwintered, seedheads of burdock (Arctium sp.). If so, the little grubs are likely the larvae of the Burdock Seedhead Moth (Metzneria lappella), a variety of microlepidoptera in the family Gelechiidae. The larvae feed on the developing seedheads, then overwinter as larvae and pupate within the seedhead in the spring. Burdock is very common here in southern Manitoba and in the fall the seedheads are typically very heavily infested with these little guys. Perhaps they hitched a ride into your home on someone’s clothing, or maybe a dog. Burdocks were originally Eurasian species but they have been naturalized in North America for a very long time. I suspect the same goes for the Burdock Seedhead Moth. Regards.  Karl

Wow Karl,  that was an impressive identification.

Letter 2 – Microlepidoptera from England

Friend or foe?
April 24, 2010
We have a ‘plague’ of these in our vegetable garden which backs on to woodland. They fly when disturbed but seem to prefer to be resting. Really only need to know if they are friend or foe. Their wings shimmer slightly as if covered in fine gold leaf.
Gill Kendrick
Central England

Hi Gill,
At first we thought that this might be a Caddisfly.  According to BugGuide, which only covers North American species, “Adults resemble moths, but wings are hairy instead of scaly.”  We decided to search the UK Moths website though, and we believe we identified your insect as a tiny moth, known as Microlepidoptera, and possibly the species Micropteris calthella which is described on UK Moths as “Wingspan 7-10 mm.  Another tiny species, with a wingspan of around 8 to 10mm, this moth has metallic bronzy forewings, with purplish tinges in places. Like other Micropterix species, it has a tuft of hairs on the head.  It occurs throughout most of Britain, and can be found flying in the daytime in May and June, where it feeds on the pollen of various plants.”  An even closer match might be Eriocrania semipurpurella, which UK Moths describes as “Wingspan 10-16 mm.  The commonest and most widespread of the Eriocrania species that feed on birch, occurring throughout most of Britain.  The adults are difficult to tell apart from E. sangii without reference to the genitalia structure, but the larvae are quite different, semipurpurella being white or yellowish, sangii being quite dark grey.   The larva itself mines in a birch (Betula) leaf, forming a large blotch, from March to May. The adults fly in March and April, especially in sunshine.”  We don’t believe we have the skill to definitively identify this Microlepidoptera, but you might have better luck trying to sort through the 2012 Moth species on the site UKMoths.  Friend or Foe is relative.

Letter 3 – Moth: Unknown Microlepidoptera species

4 legged stick bug about 5mm long
January 4, 2010
I found this little guy on my kitchen wall, January 4, 2010. There’s about 15 cm of snow on the ground outside, temperature is about -1C. I’ve seen this kind of bug before both inside & outside. Any idea what it is?
Jan, Nova Scotia, Canada
2 km from Bay of Fundy, Nova Scotia

Dear Jan,
Moths that are this tiny are called Microlepidoptera, and we must confess that the proper identification of species of Microlepidoptera is well beyond our means.  Perhaps one of our readers will be able to supply an answer.

Your response is greatly appreciated. I had no idea it is a moth!
Thanks,
Jan

Letter 4 – Small Unknown Moths

Subject: Mystery bugs on black-eyed susan
Location: North Gower, Ontario
July 23, 2015 7:28 am
I’m hoping to find out what these little guys are. I’d be happy just to know a general classificiation if they can’t be identified down to species! I found them on the Cedar Grove Nature Trail in Marlborough Forest.
Signature: Suzanne

Dear Suzanne,
These sure look like moths to us, and at this time, the best we can tell you is that they appear to be diurnal.  We will file them as Microlepidoptera on our site.

Letter 5 – Microlepidoptera from Indonesia from family Stathmopodidae

Subject: what fly is it
Location: Taman Insiyur Haji Juanda, Bandung, West Java, Indonesia
February 8, 2013 1:31 pm
Hello Daniel,
I took this one on 2010, beautiful colored fly… but I wonder what is it.
Signature: Mohamad Idham Iskandar

Wow Mohamad,
We don’t even know where to begin with this one, except to eliminate what it is not.  We are confident it is not a fly, beetle or orthopteran.  Our best guess is that it is some type of moth and some of its features are similar to hymenopterans.  We wish you had additional photos.  Perhaps one of our readers will provide some information.  The antennae are unusual and there appear to be structures associated with the mouthparts that are pointing upwards as well.

Trevor suggests False Plume Moth
Looking at those heavily spiked legs makes me think it may be in false plume moths. These moths are usually small (with wingspans around 1-2 cm/less than 1 inch) and brownish in color. They have large compound eyes, thread-like antennae, and prominent labial palps. The body is slender, and the legs bear large spines.

Thanks Trevor,
We had to do important things unrelated to What’s That Bug? today, and we are satisfied that we did more than expected.

Thanks alot Daniel and Trevor,
Ahhh… (Bang on the head) I forgot about lepidoptera (scale wing). Just like what Trevor said, yes…it is small, no more than 1,5 cm long.
Sadly after looking in my photo collection from that place 2010, I only have 1 decent looking photo of them.
I only met this guy once, and until now I haven’t met them again.
If I ever met them again, I’ll take more decent photos and inform you …

Karl provides some suggestions
Hi Daniel and Mohamad:
You are quite right Daniel. This is one of those frustratingly difficult Microlepidoptera, a group of tiny moths made up of numerous families and innumerable species. I think it is likely some sort of Concealer Moth in the family Oecophoridae. They are sometimes referred to as wasp mimics, which is in line with your suggested resemblance to a hymenopteran. However, it could also be Cosmet Moth in the family Cosmopterigidae (and there may be other candidate families as well). The prominent upturned facial appendages are its labial palps, a feature that is common to all sixteen or so families of the superfamily Gelechioidea , the Curved Horn Moths, to which the Oecophoridae and Cosmopterigidae both belong. Identifying it any further would require some serious expertise. Regards.  Karl

Thanks so much Karl.  We will classify it as Microlepidoptera.

Update June 25, 2020 from Dr. John B. Heppner:
This moth is a new species of the family Stathmopodidae. Very interesting species.

Letter 6 – Unknown Microlepidoptera

Black and White Striped Unidentified insect
Location: Montana
December 31, 2010 12:39 am
Hello. I have a random insect that appeared in my home a couple days ago. I live in Bozeman, MT and I had a Fraser fir in my house and I also have a couple herbs growing in my kitchen (basil, oregano, thyme). My camera wouldn’t focus any closer but zoomed in the picture is fairly good. Thank you very much.
Signature: Jenny

Hi Jenny,
This is a moth, and since it is small, it is somewhat unscientifically categorized as a Microlepidoptera.  We tried scanning the plates on the Moth Photographers Group without any success.  It looks similar to a Clothes Moth in the genus Eudarcia that is pictured on BugGuide, be we are confident that is not the correct classification for your specimen.  We do believe your moth is neither a Clothes Moth nor a Pantry Moth, and it may have been transported on the Christmas tree.  You did not indicate if this was an isolated specimen or part of an infestation.  Perhaps one of our readers will have better luck with a species identification.

Letter 7 – Unknown Microlepidoptera

Subject: microlep?
Location: Midland, MI
July 17, 2014 6:47 am
Hi bug man,
I’m stumped! I have a microlep that I am struggling to ID. A homeowner recently dropped this moth off as one captured from her yard. She indicated this spring much of their ground cover and other assorted plants were being eaten by caterpillars, and suspects this moth as the adult.
This is not a critter I am familiar with. I also have to admit that these tiny moths are my least favorite thing to ID! Is this in the family prodoxidae?
I am also curious as to what to tell this lady… “this is a small moth. it’s a species I am not familiar with as there are thousands of tiny moths in Michigan that are no fun to key out. This species isn’t one that we see as a common insect pest, and chances are it is probably not polyphagous– eating so many different kinds of plants in your yard. It’s hard to help you ID caterpillars from months ago without seeing them nor knowing what KIND of plants they were eating.”
For fun and unrelated, I am sharing a photo of hatching cecropia eggs that I took yesterday 🙂
Signature: Elly

Dear Elly,
We agree with you fully that identifying Microlepidoptera is not easy, and we might spend hours on this and still be unsuccessful.  Your letter did not indicate why you are the point person for this identification, so we can only surmise that your work for a nursery, an extermination company or perhaps a museum.  We are posting your images and we hope that one day there might be an answer.  We suspect this moth is not related to the caterpillars that are feeding on the woman’s plants.  The hatching Cecropia Caterpillar will get its own posting.

Reader Emails

31786

Letter 1 – Possibly female Winter Moth (or Fall Cankerworm)

Subject: What kind of bug is invading my house?!?!
Location: Concord, NC
February 4, 2013 11:37 am
The past few days I have seen numerous of these lil buggers in my house. Today I found three on the back of my couch laying eggs. What is this?
Signature: Tonya

Hi Tonya,
The photo is lacking in detail, but this appears like it might be a female Fall Cankerworm Moth, Alsophila pometaria, and you can compare your individual to this photo on BugGuide and you can read about this species on BugGuide as well, which states:  “The larvae are often a serious pest of many tree species elsewhere, although it rarely reaches densities high enough to do damage in Alberta. The eggs are laid in clusters on tree branches and trunks by the wingless females and hatch the following spring, synchronized with the flush of leaves. There are four larval stages, which are described in detail by McGuffin (1988). Larvae pupate in the soil and delay their emergence until fall, spending about four summer months as a pupa. Females in at least some populations are able to reproduce parthenogenetically (without mating). (McGuffin 1988). (AEC)”.  After writing that, we found an even closer match in the female Winter Moth, Operophtera brumata, an invasive introduced species which we also found on BugGuide where it states:  “Native to Europe, introduced to Northeast and Pacific Northwest, pest species in areas such as Boston. Established in the NW since the 1970s” and “larvae feed on willow, trembling aspen, paper birch, balsam poplar, and bigleaf maple … this introduced species is a serious pest (defoliator).”  We wish you had sent a photo of the egg mass.

Daniel,
Thank you so much for responding. Looking at the photos, the bug looks more like the female winter moth, but the egg mass looks just like that of the fall cankerworm moth. I was so freaked out at first, I just wanted to get them out of my house. Then later I found another one. That is when I took the picture. If I find anymore, I will try to get a better picture for you that maybe includes the eggs. (But hopefully, not!) 🙂
Have a blessed day,
Tonya

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Moth Fly Pupa found in Toilet

moth, fly, or moth fly
Location: Washington State
February 3, 2011 2:23 pm
Found these larvae in my toilet bowl. I flushed and more appeared. I looked in the tank and found that the tank had been retrofitted with a plastic eco insert. In the main tank there was about 1/4” of stagnant water because the water was being diverted into the insert. I think that a fly or moth laid eggs in the stagnant water and then somehow the larvae moved into the plastic insert and with every flush some get sucked from the insert into the bowl. Because I don’t know how the retrofit works, I haven’t taken it apart to check.
Signature: Amsuncow

Dear Amsuncow,
We actually believe this is a pupa and not a larva, and your supposition that it might be a Moth Fly in the subfamily Psychodinae is probably correct, though your images look different from the stages of the Filter Fly, Clogmia albipunctata, that are pictured on BugGuide.  Your individual is more elongated than the this image of a Filter Fly Pupa from BugGuide, however, there are other members of the subfamily that have a similar habitat.  BugGuide also provides this information on the subfamily:  “Larva: eyeless and legless; head darker and narrower than body; each segment with one or more dark rectangular bands dorsally; terminal segment narrows, forming dark-colored breathing tube  Pupa: resembles minute grain of brown rice” and “Adults often found around sewage installations, in public washrooms, and bathrooms in homes, and are attracted to light; larvae live in organic sludge that forms on inner surfaces of drains and sewage pipes; pupae occur on the surface of the organic film that the larvae have been living in.”  Finally, BugGuide has this information on the life cycle of Moth Flies:  “In the home, females lay irregular masses of 30-200 eggs in the organic gelatinous film lining drains, particularly in bathtubs and showers; eggs hatch 32-48 hours after being laid, when ambient temperatures are 70ºF (about 20ºC), and larvae pupate 9-15 days later; pupa stage lasts 20-40 hours; development time from egg to adult is 7-28 days, depending on temperature and food availability; adults live for about two weeks.”  Since the Moth Fly Pupa are on the surface, they are easily transferred from the eco insert to the tank and bowl during the flushing process.  The appearance of Moth Flies in otherwise sanitary bathrooms might be due to poorly engineered, but well intentioned methods for water conservation.  Thank you so much for sending your letter and excellent photographs.