On various Species of the American Genus Astylus. 337 



XXXII. — Elates on various Species of the American Genus 

 Astylus, Cast., with Descriptions of their Sexual Characters 

 [Coleoptera], By Geokge Chaeles Champion, F.Z.S. 



Certain species of the Malacoderm genus Astylus, Cast. 

 {■=M(C<glossa, Soliev) exhibit remarkable sexual characters, 

 two only of which appear to have been specially noticed by 

 authors, viz., the broad, vertical lamella on each side of the 

 terminal abdominal segment in $ $ of A. trifasciatus and 

 A. gayi, mentioned by Guerin, and the deeply emarginate, 

 bispinose apices of the elytra in $ $ of A. octopustulatus 

 and A. antillarum, observed by Gorham. The presence of 

 these and other important external structures, accompanied 

 by peculiarities in the <$ genital armature (visible in many 

 dried specimens), has induced me to examine the tegmen 

 and sedeagus (penis-sheath *) of nearly all the species repre- 

 sented in the British Museum, or in that of the Hope 

 Collection at Oxford. These chitinous structures are noticed 

 in detail in the present paper ; and in a number of cases the 

 insect itself, owing to uncertainties of identification, is re- 

 described, or named, if new. The principal external charac- 

 ters observed, apart from the longer antennae or curved tibiae 

 of the males of certain specie?, are : — (1) the presence of two 

 compressed," subcorneal, tuberculiform or dentiform promin- 

 ences on the metasternum in $ (A. octopustulatus, gorhnmi, 

 &c.) ; (2) the long, spiniform, anterior trochanters in <$ 

 (A. subgriseus) ; (3) the obliquely produced or dentiform 

 inner apical .angles of one or more of the intermediate joints 

 of the anterior tarsi in <J (A. ant is, splendidus, correptus, and 

 convexus) ; (4) the posteriorly constricted elytra in $ 

 {A. correptus) ; (5) the deeply emarginate, bispinose apices 

 of the elytra in $ {A. octopustulatus, gorhami, antillarum, 

 &c.) ; (6) the sinuate-truncated apices of the elytra, with 

 sharp or dentiform sutural angle, in ? (A. quadrilineatus, 

 imbricatus, &c.) ; (7) the elongate, conical, terminal, abdo- 

 minal segment in <$ [A. sexmaculatus, &c.) ; (8) the laterally 

 lamellate terminal abdominal segment, and broadly divided 

 fifth ventral segment, in $ {A. trifasciatus and gayi); (9) the 

 forcipate terminal dorsal segment in $ (A. forcipatus) . 



The tegmen of the $ in many of the species is very 

 deeply emarginate or cleft at the apex (^4. trifasciatus, &c.) ; 

 in others it is feebly emarginate {A. octopustulatus, &c.), 

 tiuncated (A. cyanerythrus } &e.), or simply rounded at the 



* Median lobe of Sharp and Muir. 

 Ann. & Mag. N. Hist. Ser. 9. Vol. ii. 25 



