AMERICAN COT.EOPTERA. 



29 



Tribe 1. — Lampyrini. 



The most cliaracteristic structure in these insects is tlie light-givuig 

 apparatus which is contained in the posterior abdominal segments of most 

 of the species, though it is quite absent in some genera. 



The position and form of tlie organs diflfer according to genus and in 

 a less degree according to species. 



Tn most of the genera the sexes are similar in appearance, but in the 

 Lampyres -roup the $ are larger than S and larviform, with short elytra 

 and n.". wings. In these genera the eyes of the % have their maximum, 

 and those of the 9 the minimum development. In the other groups 

 the eyes of the % though larger than those of ? , are not remarkable 

 or disproportionate in size. The head is deeply immersed in the pro- 

 thorax which is foliate at the sides and apex, so as to protect the head. 



The antennas are approximate or moderately separated, and vary m 

 form according to group and genus. Our genera seem t.^ indicate' the 

 following groups : 

 Autonua' with r^ecoml joint <uin\\, usually tnmsv,.rs.-, head c-„npl.'irly covcn-.l l.y 



pnitliorax. ' ^.r th i ' 



Autoniiit. pectinate, rather .listaut,, hist j.nut siuiph- Mathetet. 



Vnl.Mun,- not pectinate, (in our genera), approximate, h.st, .imnt ehmgate, 



Photini. 



\nl!'imi.' with last'join"appen.lieuh,te, having a small aeieular ai^pendage. 



Lampyres. 



■ Ynteun:e with s.-eond joint not transverse ; head exserte.l, narrowed behin.l the 



..; LucwlcE. 



eyes 



(iroup 1. — Mathetei. 



In this group the front is wide, the antennjc moderately separated at 

 the base, eleven-jointed, pectinate ..r bipectinate, with the last jomt 

 elongate, sinuate and pointed at tip. The eyes are not very large, lateral, 

 ccjnvex, widely separated above; and beneath. 



The prothorax is less prolonged over the head than in the next two 

 groups; the elvtra are similar in both sexes and the inflexed epipleuraj 

 are wide near the base, the extreme margin being reflexed and elevated 

 as far as the length of the metasternum ; this fold is parallel with 

 the side margin in Matheteus, but runs ..bliquely' towards the latter 

 in Poli/clasis. matheteuS 



Margins expan.h-.l, flattened; antenme pectinate ^nrvrr Atq 



Margins not flattened; antenna^ hipectinat.- POLYCLASIS. 



MATHETEUS Lee- 

 Int^ennse with second joint small, third triangular, obliciue, anterior side 

 short; joints 4—10 with a long flat process about the middle; eleventh 

 elonglte-oval, acute, with a cusp on the anterior side near the tip. 



