190SS 



ENTOMOLOGICAL SOCIETY. 



75 



Procris Americana larvic feedin" 



rule only feed at night, generally confining their attacks to low plants, such as cabbages, 

 cauliflowers, etc., so during serious outbreaks apprehension as to danger to near-by trees, or 

 other crops, may, in many instances, be avoided. 



Some species of larvfe have the habit of lying close together in serried ranks when feeding, 

 and many of congregating when resting. Interesting examples of the former kind are 



Frocris Americana, Harris, Fig. 52, Attacus 

 promethea, Dru., and Hyperchiria io. Fab,, 

 which, when in their younger stages, feed in a 

 row, each larva beside the other, on the under- 

 side of a leaf. Vanessa atitiopa, Linn., and the 

 Datanas are examples of those which feed in 

 colonies, a small branch having as many as 

 fifty or more, close together, while on the 

 remainder of the tree there may not be a single 

 specimen. The two kinds of Tent Caterpillars 

 furnish splendid examples of larvte which con- 

 gregate in masses when not feeding. Everyone 

 has seen the tents of Chsiocampa Americana, 

 Harr., the true tent caterpillar, containing 

 large numbers of the larvai, and most people 

 have doubtless seen the large masses of the 

 Forest Tent caterpillar, Clisiocampa disstria, 

 Hbn., which does not make a tent, the larvsie when at rest congregating on a silken mat spun 

 on the trunk of a tree or along one or two of the branches. 



While many species of caterpillars have the habit of congregating in numbers, others are 

 quite the opposite, and are solitary throughout the whole of their larval existence, not more 

 than one, or at most two, specimens being found feeding on a single plant. A common inter- 

 esting illustration of this is Arzam a obliquata, G. & R. The larva of this species is a borer, 

 feeding inside the main stem of the common Cat-tail, Typha latifolia, L. , inside of which it 

 also generally passes the pupal state. Specimens, however, when mature sometimes leave the 

 Cat -tail and wander, or swim, to the shore or edge of the swamp to seek a suitable place to 

 pupate, — under a rock, piece of fallen branch, or in an old stump under the bark or in the rotten 

 wood. I have collected hundreds of specimens of this caterpillar in various localities and only 

 rarely have found two specimens in the same plant. These larvfe when full grown measure nearly 

 two and one-half inches long, and not possessing a.ny attractive qualifications can hardly be 

 termed beautiful caterpillars. Mr. Henry Bird, who has done such good work in if ydroecm , 

 relates the interesting habit of Hydroecia diiovata, one of his new species. In a letter to Dr. 

 Fletcher he says that "thousands of plants {Solidago sempervirens, L.) may be examined 

 without any sign of a borer. A dozen isolated ones in another neglected spot may contain 

 twenty-four larva;, not twenty-three, or twenty-five, but the two dozen to a nicety, for Mrs. 

 Duovata can count up to two without any failure when depositing her ova." Among the 

 butterfly larvie those of Pamphihi metacom,et, Harr., and some other skippers, which Dr. 

 Flet3her has specially studied, are solitary in habit. These caterpillars feed on various species 

 of Carex and curiously enough furnish themselves with a cocoon-like structure, in which they 

 live when not feeding. This interesting contrivance is placed between two of the larger 

 leaves which are drawn together and fastened by means of silk. This habit of course pro- 

 vides great protection to the caterpillar, as it is only by separating almost everyone of the 

 central leaves of a plant that their home can be found. It is altogether unlikely that many 

 have seen these caterpillars in nature, as they require to be looked for very closely. 



