276 Rev. A. Matthkws on the genus Anililyopinus. 



character in which Anibli/opinus ajiree.s exclusi\ ely with the 

 Tachi/po7'idce consists in the laminate extension of the frontal 

 covering of the head, or what might have been termed the 

 clypeus, if that part had heeu defined. I do not think that this 

 one point of resemblance is sufficient to counterbalance the dis- 

 crepancies which exist in many characters of much greatei" 

 differential importance. In the Tackijporulce the intermediate 

 coxcB are comparatively small and rather deejily and abruptly 

 imbedded in the meso-sternum, which is not in any way depressed 

 for their accommodation. In Ambli/opinus the meso- and meta- 

 sterna are of a totally different type, and the former of these 

 parts is deeply dei)ressed for nearly the whole of its length and 

 breadth to receive the very large intermediate coxa>, Avhich are 

 entirelv free ; a form jn-ecisely similar to that exhibited by 

 Philonthus and Quedms. Tlie mandibles, though of a vei-y 

 peculiar shape, are long, much ciu-ved, and armed with long and 

 very strong teeth, as in many Pldlontht ; while on the other 

 hand the mandil)les of the Tachypot idcv are for the most ]>art 

 short, robust and simple. Prom Qaediiis, to which in many 

 respects it bears a strong resemblance, Ambli/opiniis differs 

 materially in the Epistermi of the ])rothorax ; in the former 

 these parts are excessively enlarged and produced triangularly 

 until they almost meet behind the anterior coxa?, covering, as 

 pointed out by Dr. Erichson, the i)rothoracic stigmata ; in the 

 latter the Episterna ai-e small and linear, indeed, scarcely ob- 

 servable, and the 2)rothoracic stigmata are open and uncovered, 

 and large as in PInlonthus ; this important character, together 

 with the general diversity of form, Avill be sufficient to separate 

 Amblyopiiiiis from Quediiis, although in many anatomical details 

 these genera are almost identical. 



It will be observed that in the preceding paragraph I have 

 called the triangular plates, which in Quedms and some other 

 genera extend over the i)rothoracic stigmata, the Episterna, and 

 I think that I am justified in using that term, by dissections 

 Avhich I have made of the prothorax : these immersed in Canada 

 Balsam exhibit, as in diagram 8, a sutvu-e jjroceeding from the 

 anterior extremity of the prosternuiu, in a line somewhat sub- 

 parallel Avith the margin of the ])i()n(itnui lo within a short 

 distance from its base. A faint suture is also visible at the Iwse 



