32 IOWA STUDIES IN NATURAL HISTORY 
These measurements are not quite exact, as the specimens are somewhat 
distorted. 
Type: male, Antigua, July 28, 1918, L. Stoner. 
Allotype: female, Antigua, July 28, 1918, D. Stoner. 
Paratypes: males, 18 specimens, Antigua, July 28, 1918, D. and L. 
Stoner; 1 Barbados, May 16. Females, 19, Antigua, same date. 
Type and holotype in collection of the State University of Iowa; para- 
types in same and in collection of J. R. de la Torre-Bueno. 
The preceding description is frankly conventional and leaves 
much to be desired. Many structures are omitted or referred 
to very superficially, but enough has been given to fix the 
species. The ordinary descriptions of the pale do not seem to 
me to convey a definite picture; they are far too generalized 
and too subtle characters to be put into words without making 
microscopic mounts both for description and for identification. 
It is to be hoped that when Dr. Hungerford completes his 
studies, the group will be on a firm foundation of pure struc- 
ture, a condition which at present does not exist. To be sure, 
pattern in this group gives a certain individual aspect to each 
species, but unless we know the group as a whole a description 
of the color pattern is vague and conveys no mental image. 
There are other structures, quite visible, the sternites, for ex- 
ample, which should yield excellent comparative characters, but 
which do not appear to have been thus far employed in this 
family. 
In addition to the 73 adults from which the type series was 
taken, there are six nymphs in various instars. 
Family Belostomatide 
Belostoma impavidum n. sp. 
Description—Head: Tylus, long, two-thirds as long from eyes to tip as 
from anterior margin of eyes to anterior margin of thorax; the usual 
elliptical suture anteriorly; a few scattered short hairs are visible at a 
magnification of 74. Eyes one and one-half times as broad as long, 
overlapping prothorax at anterior angles. Antenne concealed, as usual. 
Rostrum free, reaching distal end of anterior coxe, thin, curved, length 
7 mm; three visible segments; formula: I, concealed; II, 3; III, 2.5; IV, 
1.2; segment III with long, narrow palps, .3 mm. long. Width of head, 
7 mm., length, 5 mm. 
Prothorax: Usual shape; anterior width, 5.8 mm., posterior, 10 mm.; 
median length 5.4 mm.; thoracie groove, 4 mm. from anterior margin; 
