1898.] 159 



longer and narrower in /. apicalis than in any of the other species. 



I. apicalis is 



^ / I \ ^ "^sry deli- 



catelooking 



little insect. 



The tooth in I. tripunctata is short and very simple (fig. 4) ; I have 



no male of I. apicalis fit for figuring. 



I. torrentium and I. Burmeisteri belong to a group with longer 



setae, and the following are their more distinctive points : — 



I. — T. toeeentittm:. II. — I. Bttsmeisteei. 



" Jaune verdatre " (Pictet). "Fauve, un peu rougeatre " (Pictet). 



" Viridis, post mortem testacea" 



(Burmeister). 



Markings on head absent, or with a ne- Usually with a sharply-defined dark 



bulous marking on vertex and frons marking between the ocelli. 



in the dry insect. 



No distinct black median vertical line Black median line on pronotum usually 

 on pronotum. well marked. 



Dorsal abdominal stripe rather narrow Stripe apparently broader, especially at 



in its whole length. the beginning. 



Tooth of (? genitalia, seen from side, No such deep excision (fig. 3). 



distinctly excised (fig. 2). 



Tooth, seen from behind, dilated before Tooth, seen from behind, broadest at the 



the apex. base, and tapering towards the apex. 



With regard to the colours, I have simply introduced them as 

 broad indications ; in dry specimens it is difficult to say what is and 

 what is not the effect of desiccation. As far as the specimens before 

 me go, torrentium is more greenish-, Burmeisteri more reddish-yellow, 

 but the material is unequal. In Scotch examples of the first-named 

 the head is often mucb clouded, while in Swiss examples there is 

 hardly a trace of darker marking thereon. The genital tooth of the 

 male is decisive however. Klapalek has figured this most character- 

 istic tooth as belonging to I. tripunctata (Sitzungsber. der Kais. Akad. 

 der Wissensch. in "Wien, Mathem.-Natura. Classe, 1896, taf . i, figs. 19 

 and 20) ; Eostock (Neuroptera Germanica, 1888, p. 160) gives a very 

 brief diagnosis of a new species, I. neglecta, and he also refers to a 

 species, I. tubulosa, briefly described by Stein (Mitt. Miinchener Ent. 

 Yereins, 1879) unknown to him. Stein says out of a tube at the end 

 of the abdomen proceed two fine bristles, which Rostock says also 

 occur in his I. neglecta. These may be what Klapalek figures {loc. cif., 

 taf. i, fig. 23), and they may be found in all the species. 



