A SYNOPSIS OF THE APHIDIDAE 7 



the Aphidina and Lachnina it is hair-like, usually being as long as the 

 claws (except in the Pterocommini, in which it is considerably 

 shorter than the claws). The wings are membraneous and hyaline 

 (except in certain Callipterini, Lachnini, and Macrosiphini), and are 

 held roof -like over the body when at rest (except Monellia, Phyllox- 

 erinae, Hormaphidina, in which they lie flat on the abdomen). The 

 veins of the fore wings are as follows: the costal and subcostal are 

 almost parallel with the anterior margin; the radial extends from 

 the posterior margin of the stigma to the outer margin of the wing, 

 being either curved or straight ; the discoidals, three in number, extend 

 from the subcostal to the posterior margin of the wing. The outer 

 or third discoidal (media, cubitus of some authors) may be simple 

 (Hormaphidina, Pemphigina), absent (Phylloxerinae), once-branched 

 (Schizoneurina), or twice-branched (Aphidinae, except Toxoptera). 

 On the anterior margin of the fore wing is a dusky spot located be- 

 tween the wing margin and the subcostal veins, and between the 

 distal ends of the costal and subcostal veins, known as the stigma or 

 Pterostigma. It is usually trapezoidal in shape, and does not extend 

 to the tip of the wing (except in Longistigma and Mindarus, in which 

 it reaches well beyond the tip of the wing). The hind wings have 

 one longitudinal and either one or two transverse veins. 2 In the 

 Pemphiginae and Phylloxerinae dorsal wax glands are sometimes 

 present on the thorax, in which case their number, shape, and posi- 

 tion are of more or less specific importance. 



The abdomen consists of nine more or less similar segments. The 

 coloration of the various segments, especially in species in which the 

 color is variegated, is sometimes of specific importance. In certain 

 species wax glands are present on the abdomen (Phylloxerinae, and 

 particularly the stem mothers of Pemphiginae) and may be of use 

 in making determinations. In the Aphidinae the presence or absence 

 and location of small lateral and dorsal tubercles are often important. 

 The anal segment consists of an anal plate and a cauda. The cauda 

 may not be separated from the abdomen (Pemphiginae, Lachnina), or 

 it may be short and conical (Aphidini), short and globular, being 

 constricted in the middle (Callipterina), or it may be long and 

 ensiform or sickle-shaped (Macrosiphini). The anal plate is usually 

 well rounded, being half-moon-shaped, or it may be emarginate or 

 bilobed (Callipterina). On the sixth (or fifth?) segment is a pair 



2 For a full discussion of the venation see Patch, Edith M., Homologies of the 

 wing veins of the Aphididae, Psyllidae, Aleurodidae, and Coccidae, Ann. Entom. 

 Soe. Am., vol. 2, pp. 101-136, June, 1909. 



