12 NEW CALIFORXIAN APHIDIDAE 



Davis and Wilson for determination. The first two reported 

 that they were unacquainted with the species, while Wilson 

 identified it as L. pseudotsugae Wilson, a species he had described 

 from Douglass fir, in Oregon. After a careful study of a large 

 series of specimens of this species, and a considerable number of 

 cotype specimens of Lachnus pseudotsugae Wilson, the writer has 

 come to the conclusion that they are distinct species, the Cali- 

 fornia one being new and undescribed. Consequently it is 

 herewith described as a new species, being named after its host 

 plant, Pseudotsuga taxifolia. This aphid is of medium size, and 

 is found on the older growths of the small limbs, and on the 

 trunks of young trees, being a bark-feeder. Cotype specimens 

 are in the writer's collection, and in the collections of E. O. 

 Essig and of the University of California under the serial number 

 EOF 36. 



Alale viviparoiLS females. — The body is covered with a slight pulverulence, 

 causing it to appear quite pruinose. The ground color of the body is amber. 

 Head dark amber, about the same width as the prothorax, or perhaps slightly 

 narrower. Eyes black. Antennae (fig. 20) reach to the base of the abdomen, 

 and are covered with stiff, bristle-like hairs, which arise from small but promi- 

 nent tubercles. Segment I dark-amber, II dusky-yellow, III light-yellow with 

 apex dusky, IV light-yellow with apical one-third dusky, V light-yellow with 

 apical one-half dusky, VI dusky. The usual primary sensoria are present on V 

 and VI, and the usual accessory sensoria on VI. Segment III has from three to 

 seven rather large cii'cular secondarj' sensoria in a more or less straight line, the 

 first and the last shghtly smaller than the others. There are one or two second- 

 ary sensoria at the apex of IV. The number of seasoria varies somewhat in the 

 different individuals or in the two antennae of the same individual. Of twenty- 

 two segments (III) examined three had thi-ee sensoria, four had four, eleven 

 had five, six had six, and five had seven. Of twenty-two segments (IV) exam- 

 ined, nineteen had one sensorium, and thi-ee had two sensoria. Besides the 

 primary sensorium on V, there may be one secondary sensoriimi, although 

 this is not always so. The beak is dusky yellow with the apex darker, and 

 reaches almost to the thii-d coxae (1.1 mm. long). Prothorax with anterior 

 haK dark amber, posterior half black, about the same -^ddth as the head, or 

 slightly wider, and with prominent lateral tubercles (.018 mm. long). Tho- 

 racic lobes black. Abdomen pruinose, the ground color being amber, with two 

 rows of marginal black spots on each side. The cornicles (fig. 26) are short, 

 being scarcely more than a black ring about .037 mm. in diameter. In many 

 specimens the cornicles cannot be distinguished, but in either cleared material 

 or specimens mounted on the side they are discernible. The cauda is well 

 rounded, being half-moon shaped, with the distal margin dusky to black. 



