242 



Benj. D. Walsh on the Insects inhabiting the Galls 



same as in Tenthredo, except that B and B' are less obviously conflu- 

 ent, there are consequently nine bullae. Thus it will be seen that the 

 number of bullae in this family differs in different genera from eleven 

 to eight. In Ichneumonidse it differs in different genera from seven to 

 four, calling the spots F and G bullae, as they evidently are homolo- 

 gous with A — E. 



As is also the case in Ichneumonidse, the bullae are most distinctly 

 .seen in those species which have blackish wings; yet they are percep- 

 tible in certain lights in all species, even in those which have perfectly 

 hyaline wings. But in certain genera and subgenera, e. g. Hi/lot oma, 

 Tenthredo {taxoims'), Tenthredo (selandria), Dolerus (= Dosytheus) 

 and Emphytus, but not in Gimhex nor Tenthredo (pachyprotasis), there 

 exist in species with blackish wings, in addition to the white bullae, 

 white streaks running in a fixed and definite pattern, from one bulla 

 to another, and always located in certain slender folds between the 

 main veins, which folds are found equally in such genera and subge- 

 nera as do not possess these streaks, and also in Ichneumonidse, tkc. 



The annexed Figure 1 shows the whole system of bullae and bullar 

 streaks — magnified about six diameters — as it is exhibited in the front 

 wing of Tenthredo in Taxonus tacitus Norton or Selandria fumipennis 

 Norton. FIGURE 2, repre- Figure 1. Front wing of Tenthredo. 



senting the front wing of 

 Ichneumon, is repeated here 

 from Proc. etc. V, p. 209, 

 the homologous bullae being 

 lettered alike in both, so 

 that the eye may catch at a 

 glance the homologies of 

 the two systems. Moreover, not only is there a definite system of bul- 

 lae in the hind wing, as well as in the front wing, of Tenthredinidse, 



Figure 2. 



Front wing of Ichneumon. 



just as I have stated to be the case 

 in Ichneumonidse, (Prvc. &c. V, p. 

 213,) but in those species which 

 possess bullar streaks in the front 

 wing, there is a corresponding 

 system of bullar streaks in the hind 

 wing also, passing through the bullae and and bifurcating as in the 

 front wing. But to dwell in detail on all these points would be te- 

 dious. 



j? E 



