INSECTA. 507 
the mandibles as macxille. According to this view the mandibles 
would be wanting.) These insects undergo complete metamorphosis. 
At first the larva has six feet and two threads at the abdomen, 
(somewhat the form of Lepisma); afterwards these fect disappear, 
for the insect then lives in the abdomen of larvee of ymenoptera. 
In these Hymenoptera, also, the parasite is changed into a pupa, 
which in the perfect Hymenoptera projects between the rings of the 
abdomen. The wingless female remains in this situation, and is 
impregnated there. It is viviparous. The six-footed larvee, which 
in the genus Xenos jump like Podurelle, were described by Kive 
and WEstTwoop, and previously also by Von Srezoxp, as parasites. 
Comp. on this order W. Kirsy, Strepsiptera, a new order of 
Insects, Linnean Transact. Vol. x1. 1815. pp. 86—122, Tab. 8, 9 ; 
Addendum, pp. 233, 234 ; Lracu on the Lhipiptera of LATREILLE, 
Zool. Mise. ut. pp. 133—136 ; W. B. PICKERING, Observations on 
the Economy of the Strepsiptera, Transact. of the Entomol. "Soe, 
London, 1. 1836, pp. 163—172, PL. xvir ; J. O. Westwoop, Descrip- 
tion of a new Strepsipterous Insect, ibid. pp. 173, 174, PL xvi. 
fig. 15; C. Tu. v. Stmponp, Ueber Xenos Sphecidarum und dessen 
Schmarotzer, Beitrage zu Naturgeschichte der Wirbellosen Thiere, 
1839, s. 72—87, Tab. m1. figs. 62—74 3 by the same Ueber Strep- 
siptera, in Ericuson’s Archiv J: Naturgesch. 1x. 1843, s. 137—162. 
Tab. vit. 
Family VIII. Strepsiptera s. Stylopide. [Characters of the 
order. | 
* Tarsi with four joints. 
Xenos' Rosst. Antenne bipartite, single at the base, triarticu- 
late, with first joint obconical, longer, with branches semi-round, 
acuminate, not articulate. 
Sp. Xenos Peckii, Kirpy, Linn. Trans. Tab. 8, Tab. 9, fig. 1, Kirpy and 
Spence, Introd. to Entom. t. Pl, 11. fig. 1; the larva infests Polyste fucata 
(nor. Amer.) ; &c. European Species are Xenos Rossii and Xenos Sphe- 
cidarum. They are all small insects whose body is only about 14 line 
long. 
Stylops Krrpy. Antenne bipartite with stem single, biarticu- 
late, upper branch triarticulate, (Antennz have six joints, the third 
! £évos or Eetvos, a guest ; because harboured by other insects. 
20—2 
