232 Mr. D. Sharp's Contrihvtions to the 



extremity of tlic 7tli segment, bencatli ; this notcli is of a 

 ])ccuhar shnj^e, l)clng somewhat contracted at its entrance, 

 in front of it the seo-nient is a little impressed; the 6th 

 segment has the hind margin broadly hnt slightly emar- 

 ginate. 



Ega ; three male specimens ; also one from Santarem, 

 but I am not sure that this indication of locality is correct. 



I have also from Ega two female individuals of a 

 Lathrohlutn, which I had at first described under the name 

 ofX. qiuidraliculle, but on re-examination I think ithig-hly 

 probable that they may be females of/,, opab'sccns, from 

 which they differ by being much larger and broader,^ their 

 length being 5^ lin. I have ascertained by dissection of 

 one of them that it is a female; the ventral i)late of the 

 7th segment is not rounded in the miiltlle, but is very 

 slightly emarginate; the dorsal lobe of the 8th segment is 

 very compressed at the extremity, so that it appears to 

 form a sharp longitudinal carina. 



3. Lathrohium decisum, n. sp. L. opalescenti omnino 

 similis, notis sexualibus tantum differt. 



Mas: abdomine segmento 7° ventrali apice medio ]n'o- 

 funde, sat late semicirculariter exciso : segmento 6" late 

 profundeque longitudinaliter impresso, apice medio emar- 

 ginato, utrinque angulatim producto. 



Tapajos ; a single male. 



I am unable to find any characters except the sexual 

 ones to distinguish this si)ecies from L. ojKdesccns, but 

 these are very marked and important. The notch of the 

 7th segment is narrower and deeper, not contracted at the 

 entry. TIic 6tli segment has a broad and deep longitu- 

 dinal impression along the middle ; the sides of this impres- 

 sion are remarkably al)ru})tly defined, and ])r()ject beyond 

 the hind margin, so as to form an acute angle. 



I have also, from the same locality, a female individual, 

 which I believe to be the other sex of this species; it is 

 about the same size as the male ; it has the hind margin 

 of the 7th segment beneath slightly emarginate in the 

 iiiiddk-; it dilfcrs from the female dcscril)ed as that of Z. 

 opali'scciis by its much smaller size, and l)y the shorter and 

 much less laterally compressed dorsal lobe of the 8th seg- 

 ment. 



■1, T.idhrohium pnncflcrps, n, sp. Pleeo-rufum, niti- 

 dum. antennis pedd)US(]ue rufo-testaceis ; capite subopaco. 



