MEMBRA GIDJE. 
179 
TRACHYTALIS ISABELLINA, Fowler. 
(Plate XXXVIII. figs. 1, la-c.) 
Fowl. l.c. Tab. VII. figs. 25, '25a, p. 115. 
Distinguished from Micrutalis by the large central discoidal area of the tegmina, 
and by the long posterior process of the pronotum, which reaches as far as the tips 
of the tegmina. 
The above species is of a dark dun colour, more or less mottled with brown and 
densely punctured. The tegmina are transparent, with the margin near the base 
brownish and punctured ; legs fuscous. 
Figured from Canon Fowler’s private collection. 
Size, 5x2 mm. 
Habitat. —Mexico, Chilpancingo, 4000 feet; and Orizaba. 
TRACHYTALIS DISTINGUENDA. 
Fowl. l.c. p. 115. 
By description very like the preceding ; lighter in colour, but with a more sinuous 
margin to the dorsum. 
Habitat. —Cuernavaca, in Morelos. 
Genus: POLYGLYPTA (Bunn). 
Fairm. l.c. p. 29G. Stab Walk. l.c. p. 542. Fowler, l.c. p. 121. 
Fairmaire describes eleven species of this remarkable genus, all of which hitherto 
have been found in Mexico and parts of Central America. 
The claims to some of these to be true species may be doubted. One chief 
character employed by former authors for distinction, is the number of parallel ribs or 
carina? on the pronotum, called by some costae. These may be counted as three, 
four, or five, on each side of the central carina. But there is some difficulty in 
deciding the character of the lower pronotal margin, which may easily be confounded 
with the true carinse of the tegmen. 
Canon Fowler states that more than two hundred specimens are comprised in 
Messrs. Godman and Salvin’s Collection from Central America; but these examples 
run much into one another, and also show such variability, that Canon Fowler thinks 
they may be ranged into not more than four or five species. 
The greatest number of synonyms range themselves under the heads of Polyglypta 
costata and Polyglypta dorsalis. 
I have ventured to figure more than five species, but there must be many more 
undiscovered. It is difficult to say what is a species, where neither colour, markings, 
size, nor form are accepted as certain guides. We must hope for greater certainties, 
when the habits and field economics of these insects become better known, 
