INTOMOLOGICAL NEWS. 283 
¢, and often the anterior annulus of the first segment also 
re a plate. 
The SME cots acarusah te count ne 
much the larger. The first and usually the second pro- 
MRA Gist ineicthoracic flates are so cleft from behind 
he median line as to form two plates placed side by side. 
side these dorsal plates the body is well armed with very 
wt bristling hairs and a few long ones. The posterior an- 
18 of each abdominal segment bears two pairs of long bris- 
- thing g hairs on its dorsal and ventral surfaces and one or more 
sin hairs on its lateral margin. The anterior annulus of 
| the thoracic segments bears similar hair These hairs are 
pees 1 upon low papilla and are usually curved rather than 
fa One or both pairs on the dorsal surface of the 
a. trior segments may be mounted upon the dorsal plates. 
; : larve possess the prothoracic air nipples, as in the other 
So far as I have been able to determine, these are 
used for respiration, unless perhaps when the larve leave 
he water and crawl up the sides of the jar or along on the 
Straws and weeds which extend above the water. At this time 
they have only a thin film of water around them and the four 
_ small projections bearing the cilia which protect the posterior 
breathing pores are usualy retracted so tht these breathing 
pores are closed and at such times air may be taken through 
___ While feeding and while in the water respiration is carried 
mn entirely through the posterior, spiracles. It is interesting 
_ to watch this operation. After the larva has been at the 
bottom of the jar feeding for a while, a small bubble of gas 
to form at the tip of the breathing tube. This is 
ar 
 ontinued until the bubble has reached a considerable size, when 
the larva stops feeding, lets go all hold, and rises to the sur- 
_ face much as an zronaut. On reaching the surface the bub- 
_ ble bursts, the cilia around the spiracles spread out and hold 
the larva in place until a new supply is drawn into the tracheal 
system, when the cilia are retracted and the weight of the body 
of the larva carries it to the bottom of the jar again, where 
it continues to feed. The fresh air in the tracheal system is 
