1 66 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



the species secrete the anal fluid, while closely related species (e.g., 

 Enchenopa ferruginea) are favorites with the formicide herdsmen. 

 Ants which are commonly found attending membracids in north- 

 eastern United States are Formica obscuriventris Mayr., Formica 

 exsectoides Forel, Camponotus pennsylvanicus DeGeer, Cremato- 

 gaster lineolata Say and Prenolepis imparis Say. 



Life Histories. 



Most, if not all, of the New England species winter over in the 

 egg stage and the first appearance of the insects in the Spring is 

 the emergence of the nymphs from the winter eggs, which occurs 

 from late April to early June according to the locality, the weather, 

 and the species concerned. Mating begins almost immediately 

 after the insect reaches maturity, and oviposition occurs within a 

 week after mating. The eggs are laid usually in the bark of young 

 stems, in the buds, in the midribs of leaves, or in the soft stems 

 of herbaceous plants. The place and method of oviposition is 

 apparently very definite for each species and varies within a genus. 

 In most cases the egg-slits are very superficial and the eggs are 

 but poorly protected by the overlying epidermis, bark, or bud 

 scales ; in some cases the tips of the eggs are plainly visible. The 

 mechanics of the process differ decidedly in the various species and 

 the appearance of the egg-slit is often a good clue to the species 

 concerned. The number of eggs in the egg-mass and the arrange- 

 ment of the eggs with respect to each other and to the slit also 

 show considerable variation but the most common appearance is 

 a palmate arrangement of from three to six white, club-shaped 

 eggs in a shallow, curved slit, the tips (anterior ends) close to- 

 ' gether and the bases somewhat separated one from another. The 

 time of hatching depends to a large extent upon climatic con- 

 ditions and often the eggs of a single egg-mass show a consider- 

 able variation in this respect. The process of hatching has been 

 observed for many species and shows no unusual features. The 

 eggs become swollen a few days before hatching, the chorion 

 about the neck and upper end cracks and, sometimes several days 

 after the cracking of the egg, the cap is forced upward and the 

 head of the nymph appears, quickly followed by the thorax and 

 abdomen and more slowly by the legs. The time required for the 

 process, from the time the head is first seen until emergence is 

 completed, is usually about half an hour. 



Five instars are shown in the development of the nymph. Each 

 of these instars is distinct enough to be recognized, and displays 

 characters sufficient not only for the recognition of the species 

 but also for the identification of the particular stage of develop- 

 ment that it represents. The most important of these characters 

 are the number, arrangement and shape of the dorsal spines, the 

 structure of the prothorax and the configuration of the head. 



