289 



The egg (Fig. 23, c,d). — Length O.c millimetre. Elliptical ovoid, greenish or 

 yellowish-brown when first laid, but gradually changing to a shining black. Depos- 

 ited on the twigs, preferably about the buds, but often on the bark away from them. 



The Cabbage Aphis. (Jjjhis Irassifce L.j 



Although this insect has beeu known both in Europe and America 

 lor more than a century, the sexed forms and eggs seem never to have 

 been described. Early in November I found on the Cabbage leaves, in 

 company with colonies of winged and apterous viviparous females, the 

 eggs, oviparous females, winged males, and a form which I conjectured 

 to be the wingless male. The winged males were observed in cojiula 

 with oviparous females a number of times, and the eggs were obtained 

 both on the leaves and from Aphides in confinement. 



The winged male is shown at Fig. 24, a. It differs from the winged 

 viviparous form principally in the smaller size of its abdomen. The 

 oviparous female is represented at b of the same figure. It is easily 

 distinguished from the apterous, viviparous form by its more slender 

 body and tapering abdomen. 



DESCRIPTION. 



Winged male (Fig. 24, a). — Body, 1.2 millimetres long: head to tip of folded 

 wings, 3 millimetres; wmg expanse, 5 millimetres ; antennse, 1.6 millimetres. 



Body small; head and thorax brown or black; abdomen light greenish-brown, 

 with rows of black spots arranged transversely on dorsum. Legs black, except proxi- 

 mal portions of femora, which are brown. Cornicles dusky, rather short, subcylin- 



DcUners, del. 



Fig. 24. 



-Aphis brassicce: a. wlDged male, mao:nified: b. head and antenna of same, more magnified; 



■viparous female, magnified ; d. bead and antenna of same, more magnified (original). 



