March iS.,6.] 



PSYCHE. 



z: 



■ >;> 



At such times thev ;iiso wave their 

 long hind legs in the air, probably to 

 fiighten away predaceous or parasitic 

 enemies. The males are winged and 

 the oviparous fcinales wingless. The 

 egos are deposited in longitudinal 

 rows on the White Pine leaflets. 

 Each egg is not quite one-tenth of 

 an inch long, elongate-oval, brownish 

 when first extruded but soon chang- 

 ing to shining black. 



Besides tlie aphides liv- 

 ing upon leaves and ovi- 

 positing upon twigs, ami 

 those living upon twigs 

 and ovipositing upon 

 leaves, there are many 

 species which both live 

 and oviposit upon the 

 twigs. Several such forms 

 occur upon willow, the 

 prettiest one being the 

 Spotted Willow Apliis 

 ( Melanoxatitkus salicis) . 

 This insect lives overwin- 

 ter in the egg state on 

 the l>ark of willow twigs. 



summer they have often increased so 

 enormouslv as to cover all the twigs 

 of infested trees, making tliem appear 

 filthy and unsightly, as well as impair- 

 ing theii' vitality by extracting the sap. 

 In autumn a sexed generation is pro- 

 duced, the males of which may be 

 either winged or wingless. In Ohio 

 I ha\e found only winged males, wliile 

 in New Hampshire I found both forms, 

 the apterous ones being much the more 



F. Detnh'rs. del. 



Fig. I. Flocculent Willow Aphis: a, oviparous female — enlarged; l>, head 

 and antennae of same — greatly enlarged; c, eggs on willow bark — one-half 

 larger than natural sizes. 



Early in spring the eggs 

 hatch into young plant-lice which insert abundant. The oviparous females con- 

 thelr tiny beaks into the tender bark and gregate in one or a few places for pur- 

 suck out the sap. They grow rapidh, poses of oviposition. In such situations 

 and each one soon becomes the mother they often cover the bark with their 

 of several yoimg aphides. The genera- eggs. When first laid each egg is 

 tion from the egg are all wingless, but coated with a sticky liquid that dries 

 those of the second generation probably into a thin, grayish, irregular covering, 

 tlevelop into both winged and wingless closely resembling the willow bark in 

 forms, which are also viviparous. vSiic- appearance. 



cessive broods continue to a]ipear Another species, closely resembling 



throughout the entire summer, all being the spotted one, and called the Floccu- 



viviparous, and some having wings lent Willow Aphis {AI. flocciilosiis) 



while others have none. By mid- lives upon the Gray Willow in floccu- 



