132 MORPHOLOGY, ETC., OF THK MICKOPTEKYGIDiE. i., 



Micropterygidce possess this wing-spot, which all other archaic 

 Trichoptera possess, and no other insects ? The answer is, that 

 they do not; and hence they are not true Trichoptera. Pro- 

 fessor Comstock must surely explain away this discrepancy 

 before we could possibly consider the acceptance of his conclu- 

 sions. Seeing that this wing-spot is visible even in the known 

 fossil Trichoptera, we are bound to insist on its importance 

 as an essential character of the Archetype and of all archaic 

 members of the Order Trichoptera. 



There are really four important ordinal differences between 

 the wings of Trichoptera and Lepidoptera : — 



(a) In all archaic Trichoptera, M 4 exists as a separate vein in 

 the forewing. In archaic Lepidoptera, M 4 is either absent, 

 or fused with Cu ]a . 

 (6) In all Trichoptera except only the highly reduced Hydro- 

 ptilidce, the characteristic winy-spot is present. It is 

 never found in Lepidoptera. 



(c) In all Trichoptera, the tracheation of the pupal wing is 



reduced to two trachea; only. In all Lepidoptera, the 

 tracheation remains complete. 



(d) In Trichoptera, scales only appear in a few isolated and 



highly specialised genera, and are then of only very 



primitive, elongated, narrow form, witli few stria?. In 



Lepidoptera, scales of a broad, specialised form, with 



numerous striae, occur throughout the Order, from the 



lowest to the highest forms. 



Now, in the whole of the Micropterygidce, M 4 is not present as 



a separate vein of the forewing; the characteristic Trichopterous 



wing-spot is absent; the pupal wing-tracheation is complete; and 



scales of a broad form, with numerous striae, are present. On 



all four characters, then, the Micropterygidce must be adjudged 



to be archaic Lepidoptera, and not archaic Trichoptera. 



Functional frenula have yet to be found in the Trichoptera. 

 Their presence, then, in Micropterygidce is an additional argu- 

 ment in favour of the non-Trichopterous nature of these insects. 

 As true frenula occur in the Orders Mecoptera, Planipennia, and 

 Lepidoptera, and a true jugal lobe, resembling that of Rhyaco- 



