OF WASHINGTON. 107 
To complete this short review of the insects found on Uniola, it still re- 
mains to be mentioned that the stems deserted by the Mordellistena fre- 
quently become the abode of numerous specimens of a Ptinid beetle of the 
genus Hemiptychus, the larvae of which feed upon the debris left by the 
Mordellistena larva. 
Mr. Schwarz made a communication regarding the correlation 
in the increase of the number of mosquitoes on the one side and 
certain species of dragon-flies on the other side, as observed by 
him in the months of May and June, at Biscayne Bay, in south- 
eastern Florida. 
The following is an abstract from his remarks : 
Mosquitoes abound in that section of the country at all seasons, but when- 
ever the regular tirade wind ceases to blow they enormously increase in 
numbers and become a most serious pest, which greatly interferes with all 
out-door occupations, especially in the hammock lands. During such mos- 
quito spells there is an equally sudden and great increase in numbers of 
certain dragon-flies, and this is the more interesting because there is a great 
scarcity of fresh water in the country south of Miami River. It may be 
presumed, however, that most of the dragon-flies come from the Ever- 
glades to the shore of Biscayne Bay, a distance of about 7 or 8 miles. 
Three species of dragon flies, Celithemis eporina, Libellula auripennis, 
and Anax /w^5,were thus incredibly abundant at times, while two or three 
others did not participate in this increase. 
Mr. Schwarz also mentioned a peculiar habit in Danais bere- 
nice observed by him at Biscayne Bay, Fla. Whenever the cut 
weeds and shrubbery were burned on the cleared patches, these 
butterflies congregated in great numbers on the heated rocks close 
to the line of the fire. 
Mr. Smith exhibited a specimen of Cicindela Belfragei, which 
shows a curious abnormity in the shape of an acute tubercle on 
the left side of the prothorax. 
Mr. Smith also called attention to some modifications of tarsal 
structure among the Arctiidcz. He finds that some genera, as 
Leucarctia and Ecpantheria, have the claws cleft to the base 
others, like Phragmatobia and Pyrrharctia, have them dentate 
at the tip, while in Spilosoma and Antarctia there is a distinct 
long tooth at the middle of the claw. The claws are not always 
alike on all feet. Sometimes the claws of fore tarsi only are 
toothed, and sometimes all are so in any case the anterior claws 
are the ones modified. What value this character should have is 
yet uncertain. 
