190 



Aside from the peculiar structures of this insect it is interesting in 

 furnishing two forms of the malej a normal form departing less from 

 the family tyi^te than the abnormal form, which has characteristically 

 enlarged and spinose antennae and swollen and curved hind thighs. 

 In these two specialized characters, however, there is considerable 

 variation, in some specimens the antennae being twice as thick as in 

 others, while again the hind thigh is sometimes much less noticeably 

 thickened and curved, but approaches more nearly to that of the nor- 

 mal male. 



There is also slight variation in all details, both as to coloration and 

 xelative proportion of joints, and detailetl armature of legs and antennae, 

 -a fact which is brought out very strikingly by the examination of over 

 :200 specimens. 



Eheumatobates rileyi Bergroth. Imago $ (abnormal form). — Length 2.2 to S"^'". 

 Velvety black, disc of abdomen slightly iDruinose ; under side of head and thorax, 

 anterior coxse, except behind, basal two-thirds of anterior femora, middle coxae 

 beneath and at base, hind coxae, basal part of hind trochanters, a central spot on 



Fig. 18. — Rhetiinatobates nleyi—normal male, enlarged, tlie lo^er figure showing abdomen from side 

 <Heidemann, del.). 



each ventral segment on lateral margins of aljdomen, basal one-third of first anten- 

 nal joint, a transverse subquadrate spot ou i^ronotum and either a triangular, heart- 

 shaped, lozenge-shaped, or linear spot on mesonotum, all yellow or yellowish- white; 

 on mesopleura, some distance above middle coxae, is an oblong darker yellow spot. 

 Head about as long as width between eyes; tylus prominent, about as long as wide. 

 Eyes large, subglobular, strongly faceted, with a tubercle beueath and furnished 

 with two or three long hairs issuing from posterior margin. Eostrum 3-jointecl, 

 short, stout, acuminate at tip, and extending to between anterior coxae ; joint 1 stout- 

 est, about as long as 3, 2 slightly longer than 1 and 3 together, acuminate. Antennae 



