caterpillars of Lepidoptera ; they begin to feed as soon as they are 

 hatched upon the muscles of their victim, until the whole internal 

 substance is consumed, excepting the alimentary canal. In this 

 diseased state the caterpillar changes to a chrysalis, frequently as- 

 suming the natural form, although the colour is sometimes altered; 

 but instead of a moth or butterfly, one or more Ichneumonidae are 

 produced. 



This tribe of insects, however, is eminently useful, employed as 

 it appears to be, to destroy and keep within bounds those hosts of 

 caterpillars which otherwise might frequently deprive vegetation of 

 its beauty and utility : to convince the reader of this, it will be only 

 necessary to refer him to the " History of the Brown-tail Moth, by 

 W. Curtis." 



The following are the species and varieties of this genus : 



1. P. necatorius Fab. Ent. Syst. 2. 144. 45.— Vespoides Panz.fasc. 47. pi. 19. 



Black, thickly punctured. Antennae orange beneath. Clypeus, 2 spots 

 on the shoulders and margin of scutellum yellow, base of abdomen, a spot 

 on each side the apex of the first joint and the margins of the remainder 

 of the same colour. Legs yellow, thighs partially black. Wings yellowish 

 fuscous. 



August. — South wold, Suffolk, and Plaistow marshes near Lon- 

 don : it has been bred from the pupa of Stauropus Fagi. This may 

 prove to be the other sex of the following species. 



2. P. dentatus Fa5. — Micratorius Fab. — Pini nob.— a, Chrysopus. Trans. Linn. 

 Soc. V. 3. tab. 2./. 5.-/3 Polyzonias Forst. Cent, of Ins. n. 85. 



This is the largest species, and has been taken in June by Mr. 

 Bentley and Mr. Dale, near Ringwood, Hampshire, flying amongst 

 pine-trees, in the sunshine ; and by the latter gentleman also on the 

 heathy side of a mountain near Ambleside, Westmoreland ; and 

 var. a was bred from the pupa of Lasiocamioa Trifolii. This 

 species, like the rest of the genus (indeed of the family I might say), 

 is extremely variable ; some having orange antennae not black above 

 as in var. a, others with the clypeus, palpi, and all the thighs black, 

 and yellow bands to all the segments of the abdomen ; and in var. /3 

 the thighs are ferruginous. Although there is no doubt but this 

 last is a variety only of P. dentatus^ as it seems to be a very un- 

 common example, I have not adopted Forster's name, which other- 

 wise has the right of priority. 



3. P. dissectorius Panz. Faun. Germ.fasc. 98. n. 14. 



Black thickly punctured. Abdomen chalybeous, margins of 4 first joints 

 yellow ; legs piceous, thighs partially black. Wings with a fuscous ;>pot be- 

 yond the stigma. 



I took a specimen the end of September, 1822, in the North of 

 Devon, and have since received another, which is a very strong va- 

 riety, being black, with a yellow spot only on each side of the 3 

 first segments of the body and a yellow margin to the 4th, and the 

 fuscous spot on the wings is very faint. 



A small portion of Pmus Abies (the Spruce Fir) accompanies the 

 insect. 



