114 INTERNAL ANATOMY OF INSECTS. 
one third?. A singular organ distinguishes the imago 
of this species, the use of which appears not to be disco- 
vered. It succeeds the rectum, and has on each side 
twoshort club-shaped appendages, open at the end, which 
receive trachea, and terminate in a short piece that opens 
into the anus?. 
In Hippobosca and its affinities the canal in question 
differs from that of other Diptera, in having no food-re- 
servoir; in other respects it resembles it°. 
From the above statement it appears that the princi- 
pal character which distinguishes those that take their 
food by suction, from those that masticate it, is the faculty 
with which they are furnished by means of an ample 
crop, honey-stomach, or food-reservoir, of regurgitating 
the food they may have stored up. Another distinction 
still more striking, which will appear more evidently here-: 
after, is to be seen in the saliva-secretors with which the 
suctorious tribes are furnished, to be found in very few 
masticators, by which they are enabled to render the 
juices more fluid and fit for suction. 
The only insect amongst the Aptera whose alimentary 
canal I shall notice, is the common harvest-man (Pha-_ 
langium Opilio): in this, though the stomach and lower 
intestine are remarkably simple, yet their ccecal appen- 
dages are numerous and singular; the former, which 
has no distinct gullet, is pear-shaped‘; and the latter, 
tapering downwards, and truncated at the end®; con- 
* Ramdohr, Ibid. 172. Lind. tie. 206 Lt Vie 
organ seems analogous to that with four retractile fleshy horns, ob- 
eal by Reaumur and De Geer in other species of Muscidae. 
Reaum. iv. ¢. xxviii. f. 13. a, s. De Geer vi. ¢. iii. Je NS end 
¢ Ramdohr, ¢. xxi. f. 6. PDI NEAR eae AG 
© fordrand sy, 3, BD. 
