INTERNAL ANATOMY OF INSECTS. 155 
single membrane, and are joined to the oviduct by mem- 
branous rugose cloaccE a : in the Phalangia, however, 
there are two tunics; the outer one of a cellular substance, 
and the inner one consisting of spiral fibres like trachece 
— a kind of structure which renders them capable of great 
extension b . Rifferschweils considers the ovaries as formed 
upon two primary types. — First, Jlagelliform ovaries, 
consisting of conical tubes equal in length, and inserted 
at the same place at the end of the primary branches as 
in the Lepidoptcra, the Bee, &c. Secondly, race?nose 
ovaries, consisting of short conical tubes, so proceeding 
from the primary branches as to render the ovary race- 
mose or pinnated, as in certain Neuroptcra, Coleoptera, 
and Diptera c : but perhaps their structure will be better 
understood if they are divided into agglomerate ovaries 
and branching ovaries : in the Jirst the egg-tubes form 
two bundles, in which the branches are not discernible, 
as in the Ephemera, the chamaeleon-fly, and spiders : 
and in the second the branches are distinct, as in the 
Lepidoptcra and the majority of insects. 
The number of branches varies in different genera and 
species. In Echinomyia grossa, a large fly, there are 
only the two primary branches c ; in the common dung- 
beetle {Gcotrupes stercorarius) these appear divided at 
their apex into fingers f : in Scotia, a Hymenopterous 
genus, and the butterfly of the nettle, there are three 
secondary branches on each side s : in many other Le- 
a Rifferschw. De Genital. Ins. 11. 
b Marcel de Serres in Mem. du Mus. 1819. 10!). Plate XXX. 
Fig. 12. a. c Rifferschw. ubi supr. 23 — . Swamm. Bibl. 
Nat. t. \\W.f. 8. a,f, g, h. d Ibid. i. 104. t. xv. /. 3. ii. 62. 
t. xii./. 8. Treviran. Arachnid, t. vv.f. 32. e Reaum. iv. 391. 
t Posselt Ana!, dcr Int. f. If. 28, 29. E JV. Did. d' 'Hist. 
Nat, xxx. 38/-—. Swamni. ubi supr. ii. ?3. t. xxxv,/. 3. 
