GENUS EHIZOGLYPHUS CLAPAKEDE. 19 



of abdomen; two on each posterior side, quite long, and behind are 

 four each side, three of which are about as long as the abdomen, 

 the inner pair mucli shorter. Legs rather slender, tarsi as long as 

 two preceding joints together; most of the tarsal hairs are spine-like; 

 the hair at tip of peimltimate joint is rather shorter than tarsi, but in 

 leg IV (PI. V, tig. -tl) it is about two-thirds as long as tarsus; the hair 

 at tip of tarsus not one-half length of tarsus. (Tarsus I, PI. V, 

 fig. 42.) In the female the bristles are much shorter, the humeral 

 bristle not nearly as long as width of bod}*, those on dorsum not reach- 

 ing to tip, the posterior lateral ones ver\' short, and those behind near 

 tip are scarcely one-half as long as width of body. (Vulva, PI. V, 

 fig. 43.) 



Length, 0.75 to 1 mm. 



Specimens from Lincoln Nebr. and from Atlanta, Ga., on dead 

 larvae of corn pyralid. 



Genus RHIZOGLYPHXJS Claparede. 



A suture between cephalothorax and abdomen; mandibles chelate; 

 tarsi with distinct claws; cuticle not granulate; ventral apertures 

 small; only two distinct posterior bristles on the cephalothorax, but in 

 some forms a minute intermediate pair is present; tarsi short and stout, 

 provided with some stout spines; male with anal suckers, and in some 

 cases there is a dimorphic male with the third pair of legs greatly 

 enlarged and ending in a large curved daw. The species are vege- 

 table feeders, and attack healthy living tissues, usually the part in the 

 ground. 



TyiJe. — R. hyacinthl Boisd. {echinopus Robin). 



This genus was based on the absence of a caroncle to tarsus, a char- 

 acter of variable value in allied genera. Michael uses the dimorphic 

 male as a distinguishing character, but I would rather not use a sexual 

 character for a genus, so base the genus on the two posterior cephalic 

 bristles and spiny tarsi. 



I distinguish six species in our fauna by the following table: 



Table of the Species. 



1. Tarsus I with a large spine close to the sense hair 3 



Tarsus I without a spine near the sense hair 2 



2. Abdominal bristles as long as width of body ; tarsi longer tarsalis 



Abdominal bristles much shorter than width of body; tarsi shorter... phylloxerx 



3. Tarsus I fully two and one-half to three times as long as broad longitards 



Tarsus I not more than twice as long as broad 4 



4. Body three times as long as broad; legs very short elongatus 



Body less than three times as long as broad 5 



5. Hind tarsus two and one-half to three times as long as broad; abdominal bris- 



tles longer; no dimorphic male seen rh izophagus 



Hind tarsus about twice as long as broad; abdominal bristles very short; a 

 dimorphic male is common . . .- hyadnthi 



