7# [Jf aroh, 



the tip of the third antennal joint appears only just to reach the apex of 

 the fifth joint, but in others it evidently reaches slightly beyond it. 



The 2 Sfi/loj)s is generally paler and more elongate than that of 

 S. aterrwia, but not always so. The dark basal band of the cephalo- 

 thorax does not usually' extend so far forward as the line of the spiracles 

 (except sometimes along the margins), but there may be a more or less 

 distinct median suffusion extending from the basal band to this line. 

 The wddth across the spimcles is 1"2-1"3 mm. in the examples I have 

 measured. 



2. — S. thwaitesi S. Saund. ? 



I have used this name for the parasite of A. afzeliella, since, 

 wrongly spelt thwaitei, it had been used by Sir S. Saunders for the 

 Stylops obtained by Dr. Thwaites at Bristol and supposed to be parasitic 

 in that And^'ena. As entomologists at that time did not properly dis- 

 tinguish between A. afzeliella and A. luilkella, and the latter is far 

 more subject to stjdopization, it becomes doubtful whether Thwaites's 

 species was identical with the single example I have myself bred from 

 true afzeliella. The S is extremely close to that of ^S*. melittae^ but the 

 females that I have examined are very easily distinguished by the fact 

 that the basal black band of the cephalothorax extends forwards in front 

 of the line of the spiracles, though it does not extend to the sides of this, 

 the lateral parts being of the usual yellowish or brown coloui' right to the 

 hind angles. The width across the spiracles is "9-1 mm. 



3. — 8. wilkellae, sp. n. 



Since my determinations of Stylops were completed, I have received 

 some specimens taken at Woking by Mr. Gr. C. Champion. They have 

 been recorded under the name of S. melittae in this Magazine {antea, 

 vol. XXXV, p. 144, xxxvi, p. 134, & xlviii, p. 137). Though extremely 

 similar to S. thwaitesi and S. melittae, the three males that I have 

 examined do not seem to agree in detail Avith either of these. The host 

 is supposed to have been A. wilkella, which was taken at the same time 

 in the garden, and contained female Stylops. The female of the Stylops 

 in A. wilhella appears to me almost identical -with that of S. thwaitesi 

 and therefore very different from that of S. melittae, while the males 

 seem somewhat intermediate between those of the species just named. 

 Until one gets a good supply of these three forms for the dissection and 

 mounting of parts in balsam, I do not think that their distinctness as 

 species can be positively stated, for the amount of variation is not 

 determinable in dry specimens, for reasons given at the beginning of 

 this paper. 



