94 PROC. ENT. SOC. WASH., VOL. 22, NO. 5, MAY, 1920 



adults. Nor is the separation of these larvae from the correspond- 

 ing stages of Z. Jmbbardi so easy, especially in the smaller speci- 

 mens. The bristles and leg spines are not sufficiently developed 

 to exhibit decided differences and the segments of the eight 

 jointed antennae are not very strikingly different from those of 

 lutbbardi, though in larger specimens they grow more towards 

 the type characteristic of snyderi. The terminal setae of the 

 cercus, moreover, are so small as to be generally not easy to 

 observe and they constitute, therefore, not a convenient char- 

 acter for separation. There are, however, two good characters 

 which will invariably enable one to separate with assurance the 

 respective larvae of these two species: the first is the hairs and 

 bristles of the body, for in snyderi especially when viewed against 

 a white background, as noted under the description of the pupa, 

 the dorsal hairs and bristles of the body and legs are decidedly 

 conspicuous, while in Jmbbardi they are apparently finer and 

 light colored, being scarcely visible; the second character is the 

 ^antennae which, especially of the smaller specimens, are very 

 "noticeably larger and heavier in snyderi. The relative size and 

 shape of the antennal segments of these nymphs vary decidedly 

 and seem to furnish no dependable character for separating the 

 two species. In both species the usual structure of the antennae 

 of a young nymph is as follows : 



The second segment of the antennae is half as long as the basal one and 

 noticeably smaller, being itself about as long as broad, almost globular in 

 shape; third segment slightly larger than the second and of similar shape; 

 fourth segment decidedly larger than the third and globular, the fifth still 

 larger and also globular, apically barely perceptibly pointed, sixth and sev- 

 enth scarcely larger than the fifth, but very slightly elongated and apically 

 a little more pointed; the eighth, and last, segment is basally as large as the 

 preceding one and tapers nearly from the base to a narrowly rounded apex, 

 the whole segment about twice as long as the basal width. In the succeed- 

 ing stages of snyderi the third segment becomes more elongate in the larger, 

 and presumably the more completely developed, specimens and then becomes 

 useful in distinguishing these larvae from those of hubbardi. 



In the material examined, apparently representing about three instars, 

 the individuals range from about 1 m. to ! 3 /4 mm. in total length. 



The typical material of this species is in the collection of the 

 U. S. National Museum. 



Type. No. 22880, U. S. N. M. 



Egg. 



On July 4, 1919, a number of individuals, representing apter- 

 ous chitinized adults, larva and nymphs, were isolated in small 

 vials and cells, each with a small fragment of wood. On the 



