284 ENTOMOLOGICAL NEWS. [June, ’o8 
under considerable pressure, so that the supply is not able to 
float the larva, but as soon as the pressure is released and the 
gas collects in a bubble at the tip of the tube, its buoyancy is 
sufficient to carry the larva to the surface. This operation is 
repeated every five minutes or so, depending upon the activity 
of the larva. 
A test was made to determine the length of time the larve 
could remain submerged. For this purpose a small quantity 
of kerosene was poured over the water in a small dish and 
many of the larve were found to be still active after being 
deprived of air for a day. 
PUPA. 
The pupe are oval in shape and somewhat flattened. They 
attain a length of 3.5 mm. and a breadth of .8 mm. The 
thoracic breathing tubes are much shorter than in the other 
forms, measuring about .25 mm. in length. The abdominal 
segments are well armed with numerous short, simple and com- 
pound spines. On the ventral surface the five segments pos- 
terior to the tip of the wing sheaths each has two rows of these 
spines. The first row on each segment is near its anterior 
edge and consists of four compound spines, well separated. 
The second row is near the posterior edge of the segment and 
consists of from six to nine small compound spines along the 
median line, bordered laterally by a single enlarged spine, and 
this followed laterally by a number of smaller ones. The com- 
pound spines consist of two or three small sharp spines borne 
on a low circular papilla. The posterior segment bears on its 
ventral surface a single strong compound spine, along the lat- 
eral edge of its slightly expanded base, while the tip is ter- 
minated by two slightly diverging strong simple spines with 
a broad emargination between. 
The arrangement of the spines on the dorsal surface is about 
the same as on the ventral surface. Each segment has two 
rows, but the spines of the second row are smaller and more 
closely set than on the ventral surface. Six of the abdominal 
segments bear these rows of spines on their dorsal surface, 
