498 Rev. T. A. Marshall’s Monograph of 
cubital areolets in the forewings, thus standing in the 
relation of secondary forms, like Apanteles as compared 
with Microgaster. The analogy of the two tribes is so 
close that their sepsration, as divisions of equal value to 
that of preceding tribes, is merely a matter of taste. The 
older writers down to «and including Haliday, regarded 
Dacnusa as a subsection of Alysia. The latter genus was 
first distinguished by Latreille in 1805, having for its 
type A. stercoraria, Latr., previously named Ichnewmon 
manducator by Panzer. Only two subsequent authors 
have attempted to describe the numerous allied species ; 
Nees v. Hsenbeck published 41 in six sections, and his 
monograph was greatly extended and improved by 
Haliday in the fifth volume of the “ Entomological 
Magazine,” and in a separate tract entitled, ‘ Alysia, 
Fasciculus alter,” published in 1839, and containing the 
Dacnuside. Haliday’s memoirs are so exhaustive, as far 
as relates to Great Britain and Ireland, that very few 
fresh discoveries have since been made, and his descrip- 
tions render most of the insects unmistakable. On the 
Continent nothing has appeared since the date of Nees v. 
Esenbeck’s work, 1834, except a few scattered notices, 
and Forster’s ‘Synopsis of Genera.” This last work is 
valuable as giving names to all the sections pointed 
out by Haliday, which have now become genera, in 
accordance with the modern conception of the term 
genus. But Forster’s peculiar penchant for multiplying 
genera, carried him, as usual, too far, and many of his 
divisions, especially those adapted for one species only, 
may be conveniently suppressed. The writings of 
Wesmael, which have contributed so much to the sub- 
ject of the present series of papers, unfortunately stop 
short at the end of the Optides. His collection contains 
two or three hundred Alysiids, which he would doubt- 
less have published if his health had permitted; these 
I have seen, but as every specimen required an elaborate 
process of cleaning, which I had no permission to apply, 
with small chance of good results, I was obliged to 
content myself with taking a few notes. 
The Alysiides seem to be almost exclusively parasites 
of Diptera, and especially of the fungivorous Tipulide 
and Muscidz ; the few observations which connect them 
with other orders of insects will be mentioned in their 
places ; they are all liable to a suspicion of error. 
