Tur BroLoGy OF THE CHRYSOPIDAE 1305 
first abdominal segment has been generally mistaken for a subsegment of 
the metathorax. There are without doubt ten abdominal segments in 
all the larvae. The last two segments are somewhat tubular and are 
retractile, or telescopic. 
The dorsal blood vessel is very distinct in all species seen. It extends 
along the mid-dorsal line from the prothorax to the seventh or the 
eighth abdominal segment. The vessel is usually black to grayish, or 
even amber-colored. Pulsations can be readily seen in the middle 
part. 
The pulvillus presents another modification. This is a trumpet-like 
structure, resembling the so-called ‘‘sucker’’ seen in many of the sarcoptic 
mites. The larva uses these pulvilli in walking on glass or other smooth 
surfaces, in which case the pulvilli are bent or twisted as if they were 
of rubber. It is usually stated that they adhere by suction, but the 
absence of strong musculature and the irregular border of the arolium 
appear to be against this view. Furthermore, no trace of any secretion 
could be seen by repeated observations with magnifications of all powers 
including an oil-immersion lens. Dewitz (1884b) held the view that 
there was a secretion. 
The species differ but little in morphology of the larva. The first 
segment of the abdomen in Chrysopa migricornis has definite small 
lateral tubercles, while in other species thus far seen the lateral tubercles 
are very much smaller or are lacking in this first abdominal segment. 
The other lateral tubercles differ in size in the various species. In 
C. rufilabris they are very small, in C. plorabunda they are of medium 
size, in C. oculata they are large. The stalks are short in C. rufilabris, 
medium in the oculata group, and very long and slender in the trash 
earriers (C. lineaticornis and others). The trash carriers have also a 
much shorter and somewhat humped abdomen in comparison with the 
oculata type. The modification of the abdominal setae and tubercles 
fits the larva admirably for carrying its packet. In C. cockerelli there 
are from one to three rows of microscopic hooked setae on each abdom- 
inal segment to the seventh, which assist in holding the packet in position. 
There is a difference in the color of the setae from the lateral tuber- 
eles. They are all colorless in C. plorabunda and C. quadripunctata; in 
C. ngricorns all are colorless except the two large central ones, which 
are black; in C. oculata and C. chi, all have black bases and the greater 
number are black throughout. C. rufilabris has short, colorless setae, 
and in C. oculata the setae are perhaps as long as in any species seen. 
