52 



THE AMERICAN ENTOMOLOGIST. 



Descriptive Department. 

 a new genus op proctrotrupidje. 



Didictyum*Nov. Gen. — j¥i"at/ transverse; three 

 ocelli, approximate and triangularly arranged ; 

 labial palpi 3-jointed; antennsc inserted in front 

 and close together ; in the ? hardly reaching to 

 the abdomen, 13-jointed, the two basal joints 

 stout ; joints 3-7 suddenly narrowed and together 

 not much longer than i and 2 ; 3 being twice as 

 long as the others ; 8-13 twice as stout, peduncled, 

 subequal in length, very slightly narrowing toward 

 tip : in the i as long as body, 15-jointed, joint 3 

 twice as long as any of the others, 4-15 subequal in 

 length. T'/iorax as long as abdomen, slightly wider 

 in the middle than the head, scutellum prominent- 

 ly raised, subovate and marginally ridged; legs 

 with the tarsi uniforml}' 5-jointed ; front wings 

 without stigma but with the veins forming with the 

 costa two closed cells ; hind wings with a stout 

 costal vein, reaching and broadening to basal third 

 of wing where it is suddenly bent upward. Ad- 

 domen narrower than thorax, with a short pe- 

 duncle. 



[Fig. 13.] 



DiDiCTYUM ZIGZAG : showing female from above, and male 

 and female antenna; (after Riley). 



D. zigzag, n. sp. — Average length 1.6"""'. Body 

 uniformly polished black. Legs, palpi, and an- 

 tennae reddish in female ; coxae, femora, and an- 

 tennae toward tip infuscate in the male. Pedun- 

 cled joints of antennae with a few minute spines 

 around the crown and longitudinallv striate. 

 [Fig. 14.1 



DiDiCTVUM zigzag: female from side (after Riley). 



Base of thorax and of abdomen with pale pubes- 

 cent hairs. Wings hyaline, sparsely beset with 

 minute spines which increase radially and form 

 a fringe arou nd the posterior half; the veins of 

 *A£S double; 6kltvO'(\ net. 



front wings forming a sprawling W with partial 

 cross veins proceeding from the lower angles, the 

 basal cross vein longest ; the longitudinal veins 

 with a few prominent spines. Abdomen, S , 

 showing but 4 joints, the terminal three short and 

 hardly distinguishable ventrally ; abdomen, '■, , 

 with the terminal joints more telescoped so as 

 not to be seen from above. 



12 2 s, 5 is reared by Prof. J. H. Comstock, 

 from the chrysalis of Aletia argillacea* in 

 Alabama. 



The genus is readily distinguished, by the 

 character of the venation and the structure of the 

 antennae, from Basalys Westwood with which it 

 has some affinity. 



DESCRIPTION OF A NEW ANOPHTHALMUS FROM 

 MAMMOTH CAVE. 



Anophthalmus interstitialis, n. sp. — Pale 

 rufo-testaceus, shining. Head elongate-oval, 

 deeply arcuately bi-impressed, nearly as wide as 

 prothorax. Antenna; slender. Thorax longer 

 than broad, narrowed behind, sides moderately 

 rounded, sinuate posteriorly, hind angles rec- 

 tangular, base truncate, median line impressed 

 throughout its entire length, basal impressions 

 deep. Elytra elongate-oval, feebl)' convex, mod- 

 erately deeply striate, the striae obsoletely punct- 

 ate and scarcelyfainter at the sides, sides sinuate 

 immediately behind the humeri, which arc 

 obliquely rounded, base prolonged at middle, 

 elytral interspaces distinctly but sparsely punct- 

 ured, more distinctly outwardly from the fourth, 

 the punctures on alternate interspaces almost 

 uniseriate, and each bearing a short erect hair. 

 Length, 5.4.'"™; .21 inch. 



A single ? from " Washington's Hall" in the 

 Mammoth Cave. 



The species is at once distinguished from all 

 others in our fauna by the punctured outer inter- 

 spaces of the elytra. Though plainly pubescent 

 (the lines of hairs on the elytra are easily seen 

 with a lens of moderate power) it differs from all 

 other pubescent species by the thorax being 

 longer than wide and the base of the elytra 

 obliquely prolonged. Th'e elytra moreover can 

 not be called sub-opaque, and are hardly less 

 shining than in A. Menetiiesi. It is most closely 

 allied to A. tt'iniis, which it resembles especially 

 in its very elongate form, but differs by the very 

 distinctly striate elytra. The elytra are less trun- 

 cate at base than in A. Menelriesi and the punc- 

 tures of the striae are much finer and less distinct. 

 The antennae are long and slender as in A. Tell- 

 kampjii and the form of the body is even more 

 slender. The penultimate joint of maxillary palpi 

 is shorter than the last joint. 



A specimen of A. MenetHesi from Mammoth 

 Cave, in my possession, is plainly but very 

 sparsely pubescent, there being a single row of 

 fine hairs on each elytral interspace. Twelve 

 other specimens of the same species all show 

 traces of pubesence. The smallest individual 

 among these measures but 4.8"""; .19 inch in 

 length, is somewhat lighter in color, more 

 elongate in form, and with the hind angles of 

 prothorax less acute. 



This description, without figi 

 p. 44, Bulletin 3 U. S. E. C. 



ears simultaneoush 



