MR. LUBBOCK ON TWO AQUATIC HYMENOPTERA. 139 
The legs of the second pair are somewhat more elongated, but otherwise very similar ; 
and those of the third pair are decidedly longer, an increase which is not owing to any 
particular segment. 
The legs are not flattened into oars, nor are they provided with fringes as in so many 
aquatie insects. In fact, this is not to be wondered at, as they are used in walking, and 
never (as far as my observations went) in swimming. 
The wings, though very peculiar, closely. resemble those of the other allied species. 
The anterior pair are as long as the body, and consequently rather longer in the male 
than in the female; they are between three and four times as long as broad, narrow at 
the base, gradually expanding for about two-thirds of their length, and rounded off at 
the apex. They are almost veinless; but at the base, along one margin, there is a 
thickened portion which is considered to represent the subcostal nerve. 
. The whole wing is covered by short, simple hairs; and the margin is fringed by long 
setze, those in front being, however, shorter than those on the hinder margin, where their 
length is almost equal to the breadth of the wing. 
Through the kindness of Mr. Walker, I have been able to compare my specimens with 
Polynema pusillus, P. fuscipes, P. flavipes, P. similis, P. atratus, and P. euchariformis, 
as well as with Mymar longicornis and the very curious M. pulchellus. 
In the latter species the wing is small, oval, and seated on a long process (see West- 
wood's Introd. to Modern Classification of Insects, pl. 78. fig. 16). In a specimen 
which I measured, the wing was ‘005 of an inch in breadth, and the long setae were as 
much as :0125 of an inch in length. 
The Polynemas generally have the wings broader, and the setze rather shorter; thus 
in Polynema fuscipes, which in many respects has a close resemblance to our species, 
the length of the wing is ‘05, the breadth ‘0125, and the length of the setze -0075; in 
other species they are still shorter: but in one labelled * Mymar longicornis,” which, 
however, can hardly, I should think, belong to this genus, the length of the wing is 
‘0375, the breadth ‘00625, and the length of the sete almost exactly the same. The 
general structure of the wing is similar also in Odctonus, Anaphes, and Anagrus. 
Pl. XXIII. figs. 8 & 9 represent the fore and hind wings of Anaphes fuscipennis, and it 
will be seen how closely they resemble those of P. natans. 
The hind wings (Pl. XXIII. fig. 5) are linear, narrow, and situated on a long, slender, 
chitinous peduncle. 
The peduncle has a length of ‘014 of an inch, the wing itself (026; together ‘04 of an 
inch. The wing is attached to the peduncle, not only at the extremity, but also by a 
narrow strip of membrane, for nearly half its length. It is very narrow, being only 
‘0015 in width; on the surface are one or two small hairs, and the margins are fringed 
with long setze. 
Similar hind wings occur in Polynema, Anagrus, Anaphes, Oóctonus, and other allied 
genera. In Ziíus all four wings are narrow and linear. 
Peculiar, therefore, as are the form and structure of the wings, they closely resemble 
those of other allied species, among which, perhaps, I may pertenens mention Anaphes 
Juscipennis and Anagrus atomus. 
