No. 34.] HEMIPTERA OF CONNECTICUT: APHIDIDAE. 273 



The antennae are as a rule long and slender and are armed with 

 few sensoria excepting in the males. These sensoria are usually 

 small and subcircular or oval in shape. In rare cases they are 

 elongate. 



The cauda is generally knobbed and the anal plate bilobed. In 

 some cases, however, both cauda and anal plate are rounded and in 

 the Saltusaphidina the anal plate is completely divided. 



Wax secretion is present to a limited extent. It is most promi- 

 nent in the Phyllaphidina. Here there are large abdominal wax 

 plates in all of the forms and the insects present a woolly-like 

 appearance on the foliage. Wax secretion is also present in the 

 genus Euceraphis, but only to a limited extent and in the Saltusa- 

 phidina it is especially prominent in some of the oviparous forms. 

 This holds true also in the Phyllaphidina. 



The habit of leaping is most prominently developed in the 

 Saltusaphidina as the name implies. Here the muscles of the 

 femora are greatly enlarged for this purpose. Many other mem- 

 bers of the tribe greatly approach this condition and in this con- 

 nection the genus Monellia may be especially mentioned. Others, 

 although they do not distinctly leap, drop so suddenly when 

 disturbed that they almost appear to do so. Our common 

 Symydobius on the birch is very difficult to collect on account of 

 such a habit. 



Certain species are closely attended by ants in return for the 

 honey dew excreted and some species are protected by these insects 

 by means of sheds or roofs built over colonies on the leaves or 

 twigs. 



The relations of the different subtribes may be expressed by the 

 accompanying diagram. (Fig. 27.) 



Key to Subtribes. 



1. Eyes of alate form with ocular tubercles present ; head not elongate 2 

 Eyes without ocular tubercles ; head often elongate 



Saltusaphidina, p. 289 



2. Antennae armed with many rather long prominent hairs 3 



Antennae with minute bristles or only a very few hairs 5 



3. Cornicles present • • • • 4 



Cornicles absent . Fullawayina, p. 288 



4. Cornicles cylindrical or vasiform Pterocommina, p. 288 



Cornicles truncate, enlarged at base .Chaitophorina, p. 281 



5. Cornicles present, position as usual . . . . . 



Cornicles absent above [MonaphidinaJ 



6. Cornicles rarely reduced to mere rings; insects not prominently 



woolly ; never gall makers • • 7 



Cornicles reduced to rings; large abdominal wax plates present 

 making the insects prominently woolly; occasionally gall makers 



Phyllaphidina, p. 287 



7. Cornicles variable, usually rather long and somewhat^ swollen ; 



oviparous female with an elongate ovipositor Drepanosiphma, p. 285 

 Cornicles never long, always short and truncate ; oviparous female 

 not always with an elongate ovipositor . Callipterina, p. 274 



