xin, D, 3 Bergroth: Philippine Heteroptera, I 97 



species in one or another character form distinct transitions 

 to L. robustus. Judging from the insufficient description by- 

 Walker and the still poorer one by Distant, L. descr-iptus Walk, 

 seems to be somewhat allied to rohustus, although my species 

 has a much longer rostrum, and differs in several other details. 



The genus Lethaeus now comprises species with or without 

 a transverse discal impression on the pronotum, with or without 

 a pronotal collar, with or without a Y-shaped elevation to the 

 scutellum, and species with a simple as well as with a basally 

 two-branched median vein to the corium. These discordant char- 

 acters at first sight seem of too much importance to be merely 

 specific, being in many cases common to a natural group of two 

 or more species, but are in my opinion not of generic value 

 owing to the many transitional forms. The entire assemblage 

 of groups and isolated species is bound together by ties that 

 render dismemberment difficult and unsatisfactory. 



Some authors have described species of Lethaeus said to have 

 triseriately punctate clavi, but I suspect they have regarded 

 the outermost (fourth) claval series of punctures as belonging 

 to the corium. This fourth series is in Lethaeus (and several 

 other genera) always separated from the third by an elevated 

 interstice (or vein), and the true demarcation line between 

 clavus and corium, which in Lethaeus lies outside the fourth 

 series, is often in the smaller Myodochinse exceedingly fine and 

 difficult to see, being perceptible only under a very strong lens. 

 To get a correct conception of the true external limit of the clavus 

 in the smaller forms it must be remembered that the corium 

 has typically but two regular rows of punctures near the claval 

 suture; if there are seemingly three such rows, we can with 

 very little risk of mistake assume that the third (innermost) 

 row really belongs to the clavus. "Clavo seriebus quattuor punc- 

 torum instructo" is one of Stal's generic characters of Lethaeus, 

 and I have seen no member of this genus with the punctures 

 of the clavus arranged in three rows. 



Genus PTYCHODERRHIS novum 



Body oblong. Head inserted to the eyes, triangular, broader 

 than long, as broad as half the basal width of pronotum, ocelli 

 placed very close to the eyes and antenniferous tubercles imme- 

 diately before the eyes, gula longitudirially convex, tumid, an- 

 tennae about half the length of the body, first joint passing 

 apex of head by half its length, rostrum reaching hind coxse, 

 first joint as long as head and a little longer than first antennal 

 joint, owing to the convex throat not appressed to the underside 



