MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



85 



Fig. il. — Venation of fore wiug of Ful- 

 ^ora. — After Spiiler. 



Spuler also shows that the venatiou of the Ortlioptera, especially their most generalized form 

 Blatta, is luudameutally nearly identical with that of the Lepidoptera, veins I-V being' readily 

 homologized with those of the latter group; so also with the most gene ralizcd Hemiptera (Fidgora, 

 fig. 47). We niiy also draw tittention to tlio remarkable resemblance in the venation of the 

 generalized Psocid genus Ampliientomuni, which at fir^t sight, 

 from tlie shape and size of the wings, reminds one of a Micro- 

 pteryx or Eriocei)li;ila, while it also has a few 

 scales like those of these moths. 



But that the system of venation of Spuler 

 is morphologically the correct one is fully 

 and satisfactorily proved by the ontogenetic 

 develoi)ment of the veins. Fritz Miiller 

 (Kosmos, i, p. 390) was the first to examine 



the incipient venation of two semipupal moths (€«stnia arclalus). He 

 observed that in the immature pupa the cross veins were wanting, and that 

 different longitudinal veins, which afterwards more or less completely disap- 

 peared, were present, and hence be regarded the pupal venation as the primi- 

 tive one. This view Spuler has adopted 

 and extended, and it plainly enough, 

 sni>ported by the researches of Brauer and Eedtenbacher on 

 the venation of the nymidi of Odonata, solves the problem 



of the venation of insects in general 

 and especially for Neuroptera, Tri- 

 choptera, Mecoptera (ranorpida-), 

 Lepidoptera, and Diptera. 



Spulcr's mcthfid was to strip off 

 the loose skin of a caterpillar just beginning to pupate, and examine the 

 incipient venation of the wings of tlie young pupa on the living insect. He 

 placed the living pupa in water and then, since the process of thickening 

 and resulting concealment of the veins of the wing is retarded, the tra- 

 cheal branches become slightly enlarged, filled with air, and thus are more 

 easily seen. Hence 



Fig. 48— Venatiou of 

 seraipupa of Cerura vi, 

 mtla. — After Spuler. 



trjO^ 



Fi(i. 49.— Venation of GracUaria /.yringella; A 

 otli; B. uf seuiiimpa.— After Spuler. 



W 



a-'i V vj 



Fig. 50. — Venation of Talfejio- 

 ria pieudobunibyci-'Ua . — A fter 

 Spuler. 



small pupa' from which 

 the larval skin has just been cast, and are trans- 

 parent, are the fittest objects for examination. 



The primitive and generalized condition of 

 the semipupal wing is shown in Spuler's figure 

 of Cerura vinulu (fig. 48), to which we have 

 added the numbering of all the veins. He shows 

 that the fundamental jjupal venation of Lepi- 

 doptera will also apply to Ortlioptera (Blatta), 

 Hemiptera, Trichoptera, etc. He proves that 

 the cross veins are of quite secondary and subor- 

 dinate importance. The results of Spuler's in- 

 vestigations, extended through different grouiis 

 from Tiueina to Rhopalocera, and illustrated by 

 many figures, are both interesting and convinc. 

 ing. The comparison of the venation of the 

 fore wing of the adult of Gnu-nariu si/rliu/cUa 

 (fig. 49, A), coini)arcd with that of its scmiimpa 

 (flg. 49, B). shows that the generalized venation of the latter is similar to that of Micropteryx, 

 veins IVi IVj not being connected by a cross vein with III and its branches; and veins II and 

 III with their branches, being separate. The veins and their numbering are Indicated by Spuler's 

 figure of Tahvporia j^seudolximhyviUa and one we have drawn ttf Hcpialus musteliniin (fig. 51). 



Fig. 51.— Venation of Hepia 

 discal vein ; j. .iiluum. 



Ixis mtustelinus ; rf, auterior; (/'.posterior 



