54 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Mouth-parts of Trichoptera.* — Mr. R. Lucas has studied the mouth- 
parts of Anabolia furcata. Those of the larva, which he regards as 
secondary acquisitions, are first described. The quadrangular upper 
lip, the strong mandibles, the first pair of maxillae fused as regards their 
cardines, and the second pair of maxillae completely fused, are described 
in detail. In the head of the larva there are two pairs of salivary 
glands, the first smaller pair belonging to the mandibular segment, the 
second large pair belonging to the first maxillary segment. The second 
pair of maxillae are associated with a third pair of glands — the spinning 
glands — of the mechanism and functions of which a careful account is 
given. In connection with the sensory organs of the larva, Lucas 
describes various forms of sensory hairs on the mouth-parts, and notes 
two clefts beside the opening of the spinning glands on the labium. 
They are openings of two innervated tubes, at the base of each of which 
lies a sensory cell. There are also several somewhat similar openings 
on the ventral surface of the labrum. 
The author then describes the mouth-parts of the nymph ; analyses 
those of the adult, and has notes on the salivary glands and sensory 
organs of the adult. He finds direct evidence that the adults eat ; fine 
food-particles occurred from haustellum to oesophagus. It seems likely 
that the insect first moistens its food with salivary secretion, licks it 
with the haustellum, and passes it down by help of the fine teased-out 
hairs associated with the mouth. The mandibles have quite disappeared 
from the adult ; the most important organ is the haustellum — the 
characteristic Trichopteron modification of the labium. In regard to 
the development of the parts, two general conclusions are drawn : — 
(1) The modification of the mouth-parts takes place through the forma- 
tion of imaginal discs which gradually grow to the final form ; (2) the 
first and second pair of salivary glands entirely disappear, and it is from 
the third pair (the spinning-glands of the larva) that the single pair of 
salivary glands in the imagines has its origin. 
Stigmata of Larva of Melolontha.j — Dr. J. E. V. Boas reports that 
on each side of the larva of MelolontJia vulgaris there are nine short and 
wide tracheal trunks, each of which is shut off from the exterior by a 
brown plate ; this consists of a reniform sieve-plate, and a curved bulla 
which fits into the cavity of the plate. As a fact the trunk is provided 
with a large external opening, which corresponds to the ordinary 
stigmatic orifice of insects, but it is under ordinary circumstances closed 
by the plate and bulla, and is only open during ecdysis ; at first it is 
circular, but later it becomes a cleft. 
A transverse section shows that the bulla is a simple tegumentary 
fold, the outer chitinous layer of which has become particularly firm. 
The plate forms a horizontal half-roof, which springs from one side of 
the tracheal orifice ; it is supported by obliquely set bars which spring 
from the adjoining part of the inner side of the tracheae. The plate and 
bars are purely cuticular structures. Further details are reserved for a 
fully illustrated memoir. 
* Arch. f. Naturg., lix. (1893) pp. 285-330 (3 pis.). 
t Zool. Anzeig., xvi. (1893) pp. 389-91 (3 figs.). 
