144 NEW YORK STATE MUSEUM 



eggs laid at the same time do not all develop equally, the more 

 vigorous thriving at the cost of the weaker, the latter frequently 

 perishing from lack of nourishment. Doctor Folsom records June 

 2 1st as the earliest date for affected leaves containing larvae and 

 cocoons. The species occurred in Illinois thereafter up to October 

 5th on which date larvae were common. The latest eggs and larvae 

 are killed by frost, along with the leaves upon which they subsist. 

 It is probable that this insect winters in the cocoon, though Doctor 

 Folsom thinks it may possibly survive in the adult stage. His 

 observations lead him to fix the number of broods at four, with 

 a scattering fifth generation, each requiring about a month on an 

 average for its development. The broods overlap sufficiently to 

 make their separation in the field difficult, though there are times 

 when almost all the galls are empty, indicating an interval between 

 generations. The eggs are deposited by the females in the un- 

 folded leaflets. The process has been described by Doctor Folsom 

 as follows: '"Standing at the base of this (young leaflet), she 

 wriggles her long, flexible ovipositor in between the two contiguous 

 faces of the leaflet as far as possible; at intervals a slight wave of 

 distention passes back along the ovipositor, indicating probably the 

 passage of an egg. Usually several eggs are laid on the same leaf- 

 let — sometimes a dozen or more. After many eggs are laid, the 

 abdomen of the female is noticeably smaller." The eggs hatch in 

 about six days and the young larvae, instead of folding the leaves 

 as might be supposed, in reality prevent their unfolding. This 

 species, like the clover seed midge, Dasyneura legumini- 

 c o 1 a Lintn., is very sensitive to moisture, contracting and becom- 

 ing motionless when it is dry and resuming activity with the ap- 

 pearance of moisture. The larva may pupate without making a 

 cocoon or may spin a cocoon as described by Doctor Folsom, the 

 insect remaining in the cocoon from 9 to more than 20 days. Doc- 

 tor Folsom states that the dorsal bands of black scales are much 

 larger and denser in this species than in D. leguminicola and 

 that the scales do not rub off so easily, the abdomen being usually 

 blackish. 



Gall This is simply the unfolded leaves of white clover, T r i- 

 folium r e p e n s, or the root leaves of red clover, T r i f o 1 i u m 

 pratense, adhering together and thus resembling small, thin 

 pods. The leaf substance is a little thickened, yellowish or yellow, 

 with brownish specks. 



Egg. Length .3 mm, width .075 mm, elliptico-cylindrical, with a 

 slight curvature, colorless and translucent when laid but showing 



