INSECTS, 255 
The intestinal canal of Insects is connected to the other parts 
of the body partly by a large quantity of fat (the adipose body, of 
which below), and partly by numerous branches of air-tubes, and 
so retained in its place, 
In very many Insects Salivary Glands are present; they are 
placed at the commencement of the intestinal canal. In Coleoptera, 
for the most part, they are wanting; RaAmpour found them in 
Curculio (Cryptorhynchus) lapathi, LkoN Durour, besides in other 
Curculionida, also in Bla; s, Diaperis, Mordella and some other 
Coleoptera ; moreover in the other orders of Insects they are 
present in by far the greater number of Families, probably in all 
Orthoptera, Hymenoptera, Lepidoptera, Diptera and Myriapoda. 
Amongst the Neuroptera they are wanting in Libellula and Liphe- 
mera, amongst the Hemiptera in Aphides. It is very remarkable, 
and not easily explicable, that in Panorpa amongst the Neuroptera 
the female has no salivary glands, or more correctly only small 
tudiments of them, whilst the male has them largely developed}. 
They have here the form of long convoluted canals (three on each 
side), which towards the end are turned upwards, and becoming 
thinner terminate by blind extremities. This form of blind con- 
voluted canals occurs also in the salivary glands of some other 
insects, ex. gr. of the Lepidoptera; but it is by no means general, 
for in the Hymenoptera and Orthoptera these organs appear commonly 
as blind sacs grouped in clusters. Microscopic investigation has 
demonstrated in these salivary vessels and glands, as in other 
glands, a layer of epithelial cells with nuclei.) 8 
Below the inferior orifice of the stomach in Insects very fine 
vessels are implanted, the so-called Malpighian vessels, which in 
former times were generally looked upon as organs for the prepara- 
tion of bile (vasa hepatica)—an opinion still maintained by Lion 
Durour, Owen? and other writers. It is, on the other hand, the 
' Our meritorious countryman Brants first made this interesting observation, 
Tijdschr. voor nat. Gesch. en Physiol. v1. 1839, bl. 173—198. It was afterwards also 
made known by Lion Durour (Mémoires présentés a UV Acad. royale des Se. vit. 1841, 
Pp- 582, 583, Pl. 11, fig. 169,) who overlooked, however, the rudimentary salivary 
glands in the female, 
? See the beautiful investigations of H. MeckeL, MuELLER’s Archiv. 1846, s. 2 5—35. 
% [It is not to be inferred that OWEN holds this opinion now: his Lectures were 
published many years ago, and a new edition of them is now in the press. ] 
