Subject: What’s this clutch?
Geographic location of the bug: Southern Ontario
Time: 08:19 PM EDT
Your letter to the bugman: Looked up and saw this on a Norway Maple leaf. Moist to the touch. Looked like a fat little moth. Actually made of overlaid cylindrical units. Egg clutch?
How you want your letter signed: Mike
These sure look like Horse Fly eggs to us. Here is a BugGuide image for comparison. According to Purdue University: “Females search for a place to lay a single mass of eggs consisting of 100-800 eggs, depending on the species. Egg masses of most species that have been studied are laid on the underside of leaves or along the stems of emergent vegetation growing in wetlands. Hatching occurs in approximately 2-3 days, and newly emerged larvae drop down into water or saturated soil in which they feed and develop.”
Online images of Horse Fly eggs do vary in color. Larvae of some species will develop in damp soil.