500 
Observations on the various Insects 
is the T. cerealium, which Mr. Haliday says is " exceedingly 
common on grass and cerealia. Mr. Kirby found specimens in 
the furrow of the grains of wheat. Earher in the year Mr. Vas- 
salli-Eandi detected them gnawing (as he expresses it, rather in- 
correctly, I think) the stems above the knots, and causing the 
abortion of the ear. It is at this period that their attacks are most 
mischievous. In the year 1805 one- third of the vtheat-crop in the 
richest plains of Piedmont is said to have been destroyed by this 
seemingly insignificant little insect. Whatever the causes may be 
which produce the alarming increase of these tribes, they appear 
to operate almost periodically, and over a ^ide space ; for in the 
same year (1805) the wheat-crops in England also suffered from 
a similar disease, as the communications in contemporary periodi- 
cals inform us."* The rye-spik&s also in Scotland are reported to 
become unprolific from being infested by some of these insects. 
At an early stage of these inquiries the minuter species of insects 
were so ill described that many were confounded under the same 
name, and such was the case with many of the Thrips, which had 
been called j^hysapus by every one who wrote upon the subject ; 
but at this time there are above 40 species described by Mr. Hali- 
day,-f- from whose Monograph it appears that the insect affecting 
the corn crops is a distinct species. They form an Order named 
Thysanoptera, from the plume-like fringes of the mngs, but 
they were at first included in the Hemiptera, and subsequently 
formed a section of the Homoptera : our insect is comprised in the 
Genus Thrips, and forms a Sub-genus called Limothrips, and the 
specific name is — 
5. T. cerealium of Haliday, and T. physapus of Kirby. — The 
larva and pupa are similar in form to the imago, but smaller ; 
" the larva is deep yellow, with the greater part of the head and 
two spots on the prothorax duskj'. The antennee and legs have 
alternate rings of pale and dusky : the pupa paler yellow, with the 
antennae, legs, and wing-cases whitish, the latter reaching to the 
middle of the abdomen. The eyes are dusky red, and the simple 
eves sometimes indicated by red dots."| The perfect insect is 
smooth, shining, piceous, often black, depressed, and about three- 
fourths of a line long. The male is apterous, the female winged : 
the head is ovate-truncate, concave on the crown, with a channel 
down the centre : ocelli 3, distinct, forming a large triangle on 
the crown : eyes remote from the base, lateral and oval, coarsely 
granulated; the collar not contracted: antennae inserted before 
the eyes, approximating, a little longer than the head, slightly 
* Haliday in Ent. Mag., vol. iii. p. 443. 
t lb., p. 439; and Curt. Guide, Genera 1048. 
X Ent. Mag., vol. iv. p. 146. 
