356 ENTOMOLOGICAL NEWS. [Oct., 'l/ 



bred and the young emerged in due course. The aquarium 

 swarmed with waterfleas ; as there was no other food the 

 Microvelias doubtless fed on the many Daphnias entrapped in 

 the surface film. By the end of the following April there were 

 nine adults in the aquarium and a very few nymphs. 



This little species feeds on dead or waterlogged insects in 

 the water, which it attacks in numbers, as observed in these 

 experiments. Its small size prevents it from successfully cop- 

 ing with living insects larger than itself. 



The chief structural peculiarities that distinguish it from 

 the other species, aside from its small size and antennal char- 

 acters, are the nearly orbiculate shape of the apterous female 

 and the curved posterior tibiae of the male. It is most fre- 

 quently found apterous, but the winged form is not rare. It 

 walks ordinarily in little staccato steps, although at times it 

 runs, especially when pursued off the duckweed into the open 

 pond, when it races out and curves rapidly back. Its habits 

 in general are like those of Microvelia americana, elsewhere 3 

 described, as well as the details of breeding, preparing for the 

 microscope, etc. 



No parasites of Microvelia appear to be known. Its internal 

 anatomy is also to be studied. 



The epg is clear pearly glistening white when just deposited; ellip- 

 tical; about one and one-half times as long as broad. The chorion is 

 apparently smooth seen under a low power (x6o), but under a higher 

 (x32o) appears rather sparsely punctulated in lines. Size (from 

 freshly deposited eggs) long., .45mm.; lat., .3 mm. This is an average 

 dimension, as it sometimes varies quite markedly. 



As development progresses, the egg grows darker and shortly before 

 emergence the folded up embryo is visible through the translucent 

 chorion. As already noted, the ec:gs are deposited on the under sur- 

 face of duckweed, the head end generally pointing to the edge, al- 

 though if this plant be not available they will deposit them anywhere, 

 embedded in a clear waterproof jelly or glue secreted by the female 

 for this purpose. The females carry two mature ova at a time, which 

 seem to practically fill up the entire body cavity. In hatching, the 

 egg splits along a straight line 4-7 of its, length and through this the 

 nymph escapes. Although looked for, no casting of the amnion or 



3 1910, Bueno, Can. Ent. vol. xlii, 176-186, "Life Histories of Ameri- 

 can Water Bugs, iii, Microvelia americana." 



