SOUTOVEETEX COKRUGATUS. 569 



a zig-zag form. The ridges on the anterior portion of 

 the abdomen, near the progaster, are, however, chiefly- 

 transverse, and usually one or two near the posterior 

 end are also transverse. There are, perhaps, most 

 frequently five or six of the anterior transverse ridges, 

 and ten or twelve of the longitudinal ; the latter are 

 ordinarily separated, by a space three or four times as 

 wide as the ridge. From the main ridges generally, but 

 not invariably, spring a number of short, irregular 

 ridges, not quite so thick ; they are more or less at 

 right angles to the main ridge, and. thus cross the 

 interspace between one main ridge and the next, but 

 they do not usually quite reach the next main ridge ; 

 they may do so. Sometimes they anastomose with the 

 secondary ridges from the next main ridge, forming an 

 irregular network. The whole of these markings, both 

 main and secondary ridges, are most variable and un- 

 certain. The ridges at and near the progaster pro- 

 ject much further forward at the sides than in the 

 middle ; where they run backward, forming a broad, 

 squarish indentation. The secondary ridges are, 

 perhaps, more clearly seen in the preparations than in 

 the living specimens : the contrary is the case with 

 regard to the main ridges. There are four longitu- 

 dinal rows of about four to six extremely fine, short 

 hairs on the notogaster ; it is often easier to see the 

 small papillge from which these hairs spring than the 

 hairs themselves. The ventral plate is considerably 

 smaller than the dorsal, which is sufflexed. Genital 

 and anal plates not very near together, the former 

 almost square, the latter larger and pentagonal or 

 pyriform. 



Nym]ph. 



I have never seen this nymph alive, and of course 

 have not ever bred it, I therefore, according to my 

 usual habit, refrain from describing it ; but Mr. 

 Bostock, the discoverer of the species, is of opinion 



