August, '10] 



DAVIDSON : CALIFORNIAN APHIDIDAE 



373 



widely distant, dusky, with the basal half of the joints paler. Third 

 joint with 25, fourth with 8, fifth with 6, sixth with about 3 trans- 

 verse sensoria. Unguis of sixth joint about one seventh as long as 

 rest of joint. Eyes black, ocular tubercles prominent. Prothorax 

 without lateral tubercles. Meso-thorax with four small pale spots 

 arranged in a transverse row. Legs dusky. Abdomen green, with 

 four rows of darker disk-like spots on the dorsum. These are appar- 

 ently glands for the excretion of the flocculent material which this 

 insect exudes. Body broadest at the fourth segment. Cornicles 

 absent. Last abdominal segment drawn out and blunted. Wing 

 large; stigma short, green. Insertions and veins greenish. Sub-costa 

 duskier. Third discoidal absent at the base. Hind wings with two 

 discoidals arising a very short distance apart. Lower side of thorax 

 black. Beak pale, slender, reaches second coxae. 



Fig. 28. Pemphigus ranunculi. Alate female; a, wing; &, tip of abdomen; 

 €, head and protliorax; d, antenna; c, antenna of "wingless female; f, an- 

 tenna of young (original). 



Pupa. Entirely green except wing-cases, antennae, legs, and tip of 

 last abdominal segment, which parts are slightly dusky. Eyes black. 

 Antennae as in the winged form. 



Apterous viviparous female. Green. Shields on head, antennae, 

 legs, tip of abdomen and beak dusky. Antenni-e barely one third the 

 length of body. There are four rows of circular dusky areas on the 

 dorsum of the abdomen as in the alate insect. Compound eyes very 

 small, lateral, black. Taken in March on the stalks of the buttercup 

 {Ranunculus calif ornkus) where it congregates in great numbers. 

 The insects cover their whole body except the head with a bluish 

 flocculent material. 



