104 MODERN CLASSIFICATION OF INSECTS. 
the fruit cannot ripen. There are two generations in the course of a 
year. The larve are of a glaucous colour, with numerous trausverse 
rows of black shining piliferous warts; they are furnished with 20 feet. 
The insects also undergo their transformations in society, one attach- 
ing the end of its cocoon to the end of the next. The species has 
been named Nematus grossularie by Dahlbom, who has given the 
history of the species in the Vetenskaps. Acad. Handl. for 1835, and 
who considers it as identical with the insect represented by Réaumur 
(tom. v. pl. 10. f. 4, 5.), which feeds upon the “ groselier ;” but that 
author states that his insect had 22 feet. Bouché (Naturgesch. 
p. 140.) describes the insect as the Tenthredo ventricosa Klug 
(Nematus v. Hartig, p. 196.). The Caledonian Horticult. Society has 
published a number of plans for the destruction of these caterpillars. 
(See also E. S. in Mag. Nat. Hist. No. 13.; vol. v. of the New Series 
of the Manchester Memoirs ; Hort. Mag. 1831.) Stephens has de- 
scribed an allied species (Nematus Ribesii), the larva of which feeds 
upon the red currant. 
At the end of June, 1838, I observed that nearly the whole 
crop of the young apples in the garden of my residence at Ham- 
mersmith had fallen to the ground, being then about the size of 
small walnuts; and, on opening some of them, I found the interior 
devoured by one or more larve of one of the Tenthredinide (pro- 
bably a Nematus), having 6 thoracic, 12 abdominal, and 2 anal feet ; 
the body not pilose, with thick lateral wrinkles. Its appearance in 
the perfect state will not take place until the next spring, when I hope 
to be able to add the name of this curious and destructive species. 
When alarmed, this larva emitted an odour like that of Cimex lectu- 
larius. The larva of Nematus dimidiatus feeds upon the poplar; it is 
yellow, with a black head, and large lateral black spots; it is figured 
in the Entomol. Mag. vol.i. pl. 1. f. 1., and is stated to have 14 
abdominal legs. 
The 20-footed larvee of Nematus ochraceus Hartig (p. 218.), 
found upon the willow, in society, generally attach themselves to the 
edges of the leaves, the prolegs being placed on the opposite sides. 
Here they continue to feed incessantly, with the hind part of the body 
elevated in the air, and which, when disturbed, they throw about in 
various directions. De Geer has figured the history of this species 
(Mem, tom. ii. pl. 37. f.1—11.). Réaumur also appears to have intended 
this, or a closely allied species, in his vol. v. tab. 11. f: 3—6. De Geer 
has also figured another very closely allied species, N. melanocephalus 
