MONOGRAPH OF WEST INDIAN STAPHYLINIDAE 229 



be recognized by other characters, such as the sculpture of the head 

 and the armature of the labrum. 



In most classifications of the Staphylinidae the Paederinae and 

 Staphylininae are separated by the character of the exposure or 

 concealment of the mesothoracic spiracles (sometimes called pro- 

 thoracic) or by the shape of the posterior coxae. In the case of the 

 first of these characters the Paederinae contains every degree from 

 completely free and visible spiracle to one completely hidden by 

 one of several means. The character is simply not usable for this 

 sej3aration, but it is not easy to find a substitute. The shape of the 

 posterior coxae is not a usable character in this instance. It is im- 

 possible to key out certain lathrobiids and philonthids without refer- 

 ence at this point to other characters. I have attempted to show 

 previously (Blackwelder, 1936) that these two subfamilies have 

 posterior coxae that are structurally similar. 



Studies of the larvae (Boving, 1931) confirm the opinion that 

 these subfamilies are closely related. Careful study has so far shown 

 only one fundamental structural character that distinguishes the 

 adults — the pattern of the pigmented areas on the intersegmental 

 membranes of the abdomen. Illustrations of these are given in the 

 paper mentioned above (Blackwelder, 1936). They can sometimes 

 be seen with a binocular microscope of fairly high power, or may be 

 examined readily in slide preparations under the compound micro- 

 scope. In the Paederinae the sclerotized or pigmented areas are rec- 

 tangular and are arranged in transverse rows. In the Staphylininae 

 they are triangular or irregular and are arranged in definite longi- 

 tudinal bands. 



KEY TO WEST INDIAN GENERA OF PAEDERINAE " 



1. Maxillary palpus with the last segment very small, generally subulate 4 



Maxillary palpus with the last segment as long as the preceding, obliquely 



hatchet-shaped 2 



2. Abdomen strongly margined, punctate 3 



Abdomen not margined, coarsely and regularly sculptured. LXI. Palaminus 



3. Mandibles edentate or with a single internal tooth near the base. 



LX. Araeocerus 



Inner edge of mandibles near the middle with a parallel slender tooth, which 



is oblique, and emargiuate at apex LIX. Pinophilus 



4. Prosternum not dilated under the front coxae as far as hypomera 5 



Prosternum expanded laterally and caudally, either connate with hypomera 



or very narrowly separated from them 22 



5. Antennae anteriorly flexile and strongly geniculate at first joint, basal seg- 



ment very much elongate 6 



Antennae posteriorly flexile, not strongly geniculate, basal segment not very 

 elongate 'J 



" This key, with the exception of the first three couplets, has been adapted from the key 

 In my recent revision of the Paederini (Blackwelder, 1939). 



