36 
MR. LUBBOCK ON THE DISTRIBUTION 
Crop. (PL I. fig. 13.) 
The walls of the crop are generally strengthened by a thick chitinons layer which pre- 
vents the fine ends of the tracheae from being well seen. It is also generally snrronnded 
by muscular tissue. In Acheta domestica it is provided with twelve longitudinal tracheae 
in six pairs which are joined at the base, and send off transverse branchlets at regular 
intervals . 
In Carabus there are about ten longitudinal tracheae which send out some large branches 
at acute angles, and many cross-branchlets (PL I. fig. 13). At the posterior end the 
great longitudinal tracheae are connected by a transverse vessel. 
In the larva of Lampyris the tracheae are as on the stomach. 
In Panorpa they form a network, as in Carabus. 
Stomach. (PL II. figs. 1 to 10.) 
In Bombus terrestris, B. lapidarius, B. muscorum, and B. kortorum, the stomach is 
divided into two parts : along the anterior run several large longitudinal tracheae which 
anastomose frequently, while on the posterior portion the tracheae are mostly transverse. 
In B. pratorum this anterior part is shorter than in B. terrestris. The tracheae give off 
branchlets which generally end in tufts (PL II. fig. 5), but the tubules themselves branch 
a good deal ; so that often the character is almost lost, as in the right-hand tuft in the 
figure. PL II. fig. 11 represents some of the tracheae of the larva of B. muscorum. 
The branchlets are longer than is the case in the perfect insect, and the tubules are longer, 
straighter, and fewer, — generally, indeed, only three in a tuft. In Vespa the trachea? 
resembled those of Bombus. Often, however, instead of ending in tufts, the branchlets 
terminated as in PL II. fig. 10, the long tubules running up a muscle. Opliion (PL II. 
fig. 3) is characterized by very long branchlets (one-fortieth of an inch in length, 
without a division), which at last break up more or less dichotomously into numerous 
tubules. In Tenthredo, a genus belonging to the Ichneumonidae, the type was much like 
that of Ophion, but altogether much smaller. The same is the case with Cynips lignicola. 
In Athalia spinarum and Tenthredo, as in Bombus and Vespa, the tracheae anastomose 
frequently on the front part of the organ. 
In Ichneumon the tubules are straight, or but little waved, long, few, and more or less 
at right angles with the branches from which they spring. 
In the Cricket the stomach is divided into two distinct parts. The walls of the first 
(/of Leon Dufour's fig. 19*) seem to consist of large cells, round which the tracheae run. 
They (PL II. fig. 9) are short and broad, and anastomose frequently. 
On the posterior part {h of Leon Dufour's figure) are numerous dark glandular bodies. 
A great ribbon-like trachea runs along the organ and gives off transverse branches. On 
one side these branches much resemble trees (PL II. fig. 4), and the glandular bodies 
look like some enormous kind of fruit. On the other side of the main trachea, the mode 
of branching is similar, but the branches are more elongated. 
* 
vol. vii. 
Orthopteres, les Hy 
' Mem. d. Sav. Etrang 
