A REMARKABLE NEW GENUS OF LYGAEIDAE 
FROM SUMATRA (HEMIPTERA: HETEROPTERA) * 
By Jaimes A. Slater 
Department of Zoology and Entomology 
University of Connecticut 
Many species of Lygaeidae possess fore femora that are strongly 
incrassate and armed on the ventral surface with sharp spines. Many 
workers have assumed that these powerful legs were associated with 
predatory habits and indeed as recently as 1956 Miller illustrated 
species of Blissinae ( Spalacocoris and Chelochirus) as examples of 
legs modified for raptoral purposes. However, it has been evident for 
a long time that this was at best an oversimplification and that very 
strongly incrassate and heavily spinous legs were known in such sub- 
families as the Pachygronthinae and Oxycareninae whose members so 
far studied are entirely phytophagous, whereas in the predaceous 
Geocorinae the fore femora are slender and not at all adapted for 
seizing prey. The enlarged leg is best expressed in the great subfamily 
Rhyparochrominae where nearly all of the many hundreds of species 
possess enlarged and ventrally spined fore femora. Putshkov (1956) 
and Sweet (i960) have shown that most, if not all, of the rhyparo- 
chromines are seed feeders. Thus the function of these legs remains 
unknown. They do not appear to be used in mating behavior or in 
antennal cleaning, nor to any appreciable extent in carrying food etc. 
Yet it seems unlikely that legs of this type would persist throughout 
hundreds of species in many different genera distributed in several 
different subfamilies and in all of the major zoogeographic regions 
without having an important function. Solution of this problem should 
be a matter of considerable interest to those concerned with the 
question of correlation of form and function from inferred evidence. 
Recently Sweet (in litt.) has noticed some remarkable threatening 
behavior, displayed intraspecifically by several species of rhyparochro- 
mines in defense of food, that involves the use of the fore femora. 
This may offer a clue to an understanding of this interesting biological 
problem. 
Despite our lack of knowledge of the function of these fore legs 
we do know enough of their occurrence in the family Lygaeidae to 
conclude that they are not of random distribution. The presence of 
incrassate fore femora is the predominant condition in the Rhyparo- 
chrominae, Pachygronthinae and Oxycareninae whereas they are 
* Manuscript received by the editor December 20, 1961. 
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