On various Species of the American Genus Astylus. 337 



XXXII. — I^otes on various Species of the American Genus 

 Astylus, Cast., loith Descriptions of their Se.vual Characters 

 [Coleoptera]. By George Ohaeles Champion, F.Z.S. 



Certain species of the Malacodcnn genus Astylus, Cast. 

 {^=j]Iici'ghssa, Solier) exhibit rnnaikable sexual characters, 

 two only of which appear to liave been specially noticed by 

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

 terminal abdomiiuil segment in cJ (^ of A. trifasciatus and 

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

 bispinose apices of the elytra in ? $ of ^. octopustulatus 

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

 these and other important external structures, accompanied 

 by peculiarities in the cJ genital armature (visible in many 

 dried sj)eciniens), has induced me to examine the tegmen 

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

 sented in ihe 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 antennai or curved tibiae 

 of the males of certain s|)ecies, are : — (1) the presence of two 

 comj)re.ssed, subconical, tubereuliform or dentiform promin- 

 ences on the metasternuni in ^ {A. octopustulatus, gorhami, 

 &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 c? {,A. antis, splendidus, correptiis, and 

 convexus) ; (4) the |)Osteriorly constricted elytra in ^ 

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

 of the elytra in ? {A. octopustulatus, gorhami^ antillarum, 

 &c.) j (6) the sinuate-truncated apices of the elytra, witii 

 siiarp or dentiform sutural angle, in $ [A. quadrilineatus, 

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

 minal segment in ^ {A. sexmaculatus, &e.) ; (8) the laterally 

 lamellate terminal abdominal segment, and broadly divided 

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

 forcipate terminal df)rsal segment in $ {A. forcipatus) . 



The tegmen of the c? i>i 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. cyanerylhrus, &c.), or simply rounded at the 



• Median lobe of Sharp and Miiir. 

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



