26 o 
THE STUDY OF INSECTS . 
ness and the great reduction of the anal area (Fig. 3 ° 5 ); 
while the hind wings have a widely expanded anal area. 
There is great variation within the family in the number of 
anal veins in the hind wings, the number ranging from two 
to four. The maximum number of anal veins in the Lepi- 
doptera has generally been considered to be three; but in 
certain forms belonging to this family a fourth (vein X) is 
quite well represented. 
Another remarkable feature of all me forms that we 
have studied is that in the female the bristles composing 
the frenulum are consolidated as in the male. The females 
also possess a frenulum hook; but this is not so highly 
specialized as that of the male. 
The adults fly very swiftly and during the hotter part of 
the day. They frequent flowers, thus increasing their resem¬ 
blance to bees or wasps. The larvae are borers, living within 
the more solid parts of plants. Some species cause serious 
injury to vegetation. Nearly one^iundred and fifty species 
have been found in this country. Doubtless many more 
exist; for the family has not been thoroughly studied as yet. 
The following species have attracted much attention on 
account of their serious ravages. 
The Peach-tree Borer, Sannina exitiosa (San-ni'na ex-it-i- 
o'sa).—This is the most important insect enemy of the 
peach-tree. In some parts of the country it is difficult to 
find a peach-tree that is not infested by it. The eggs are 
laid on the bark of the tree near the ground. The larvae 
bore downward in the bark of the trunk just below the sur¬ 
face of the ground. Their burrows become filled by a 
gummy secretion of the tree. As this oozes out in large 
masses the presence of the borer is easily detected by it. 
When full grown the larva comes to the surface of the 
ground and makes a cocoon of borings fastened together 
with silk. The perfect insects appear from May till October, 
but most of them in the latter part of June and early vr 
July. There is a single generation each year. The adults 
