JOUKNAL, OF ENTOMOLOGY AND ZOOLOGY 145 



May 15, 1911 — A pair were taken in copulation at 10 a. m.; at 

 8 p. m. they were still in coitii, but this is exceptional as most of the 

 pairs disengage very readily. In the morning the species is very 

 active and although the males do not fly far, they fly readily and 

 it is difficult to pick them up by hand. The females are excellent 

 fliers especially in the morning. 



Several pairs were taken in copulation and each pair was isolated 

 in a separate vial in order to ascertain the number of eggs per fe- 

 male. The clutch was determined by dissection. When the captive 

 insects began to oviposit, the eggs shot out from the body, at first 

 slowly, then more rapidly, one per second, later much slower again, 

 the eggs being extruded one at a time. The total period of ovi- 

 position required seven minutes; at the end of 60 seconds, In the 

 space between 60 and 70 seconds, 18 eggs were laid, or 1.8 per sec- 

 ond. Toward the end of egg-laying, the eggs appeared much more 

 slowly, one in two seconds. The eggs are quite sticky or viscid and 

 adhere to the glass. When the female is in danger of death, as 

 when she falls into the water, she begins, at once, to deposit the egg- 

 complement. In nature it seems probable that one egg is laid at 

 each descent to the water. As soon as the female touches the water, 

 although she has not deposited an egg all day, she immediately 

 starts to deposit the oblong black eggs. After the last egg is ex- 

 pelled the muscles of the ovipositor still go through the motions of 

 expulsion. One specimen was placed in the water and as usual be- 

 gan to deposit her eggs. She was decapitated, laid 11 eggs and 

 tried to lay still more but failed. The number of eggs laid varied 

 from 316 to 372 with an average of 347 ; the time required for ovl- 

 position varied from 7 minutes to 7 minutes and 40 seconds. In 

 most cases the number of the egg-complement Is probably between 

 300 and 400. 



DESCRIPTION OF THE IMMATURE STAGES 



Larva 



Length: Fully extended, 14-15 mm.; diameter, 1-1.3 mm. 



Body of the larva with rather abundant appressed hairs; the sub- 

 caudal enlargement with transverse rows of very small hairs, there 

 being from 35 to 40 such rows. 



