130 [Xovember, 



on the sides than on the back ; the lower part of tlie sides and anal segment reddish- 

 brown, without any black markings, the last segment hairy. The skin is smooth and 

 shining ; the feet reddish-white. Length, 11 — 12 lines. 



The larvpe feed on birch, and walk very fast and restlessly, and 

 "when touched by anything the body in lashed about furiously. The 

 flies I have taken from June 8th (which is the earliest date I have 

 noted) to the end of that month ; the earliest larvae I have seen were 

 on the 10th of the same month ; and again I find them at the end of 

 July and in August. Prom a larva which spun up on the 31st July 

 I reared the imago fifteen days after ; and from these observations it 

 is clear that the species is double brooded. The cocoon (which is 

 double) is spun in the earth. 



This species differs mainly from J^. luteus in having the abdomen 

 acuminate, with its dorsal surface black ; in the face being more 

 sharply pointed ; and in the above-mentioned difference in the alar 

 neuration. In addition to this, the habits and coloration of the re- 

 spective larvae are totall}^ different. It has clearly a near relationship 

 to N. acuminatus, Thoms., and I formerly considered it a variety of 

 that sjiecies ; but Prof. Zaddach tells me that he has a specimen of the 

 true acuminatus, and that it does not agree with mine ; moreover, 

 Thomson's species has the breast black. 



N. dorsatus has occurred in Inverness-shire, Kannoch, and Bishop- 

 ton, and is not an uncommon species. 



And now a few words regarding JSTematus luteus. In Scotland, 

 three color varieties of it occur : first (and this is by far the rarest) 

 there is the entirely lutcous form, which seems to be the commonest 

 on the continent, and is that described by Thomson ; second, there is 

 the very common form, with the edges of the mesonotum and meta- 

 notum black ; and third, there is a variety similarly coloured to the 

 last, but having besides three (sometimes two) black marks on the 

 mesonotum. That this last form really belongs to luteus is certain, 

 from my having reared it from the ordinary larva. It seems not to 

 have been described by any author, unless it be var. b. of If. Khigi, 

 (Dbm.) Thoms. (= hilineatus, Klug), which very closely resembles it. 

 N. Klugi (typical form) is without any doubt a good species. I have 

 a sj^ecimen that I believe pertains to it, which I took in Grlen Peshie. 



The only author who has described the larva of AT. luteus is Kal- 

 tenbach (Die Pflanzen-Peinde, 619). It may be found very commonly 

 on the alder, resting on the upper surface of the leaf, and eating holes 

 in its centre in a like fashion to the larva of Hemichroa luridiventris. 

 It has the head of an obscure greeniat-yellow colour, with a brown 



