some Parthenogenetic Chironomidee. 225 
newly hatched larva, as soon as it has freed itself from the 
jelly of the egg-mass, loses no time in making itself a case. 
I was not fortunate enough to observe the process of forma- 
tion, but apparently these cases consist chiefly of salivary 
secretion, to which minute particles adhere. Since I could 
never find any small empty cases, Iam led to believe that 
the larva increases the size of the original case as it grows ; 
but more observations are needed on this point, since the 
material of the case does not seem to be particularly elastic. 
The larva can turn completely round in its case and protrude 
its head from either end; in moving about from place to 
place it sometimes comes out as far as the filth or sixth 
abdominal segment, but I never saw one completely leave 
its case—in fact, it is probable that the hump on the back 
of the eighth and the large ventral blood-gills on the seventh 
segment would prevent its being able to do so. 
Before pupation the larva usually moors its case by one 
end in such a position that the other end is close to or 
touching the surface of the water. The pupa leaves the 
larval case only a short time before the emergence of the 
adult (I have not seen a free pupa, but have only found the 
skins floating on the surface of the water). A very note- 
worthy point is that the larva skin seems never to be 
completely shed, but remains attached to the abdomen of 
the pupa ; pupee removed from their cases, as well as cast 
pupal skins collected on the surface, always had the larval 
skin attached *. 
The adult, when freshly emerged, has still much of the 
blood-red colour of the larva—which, indeed, is the case 
with other Chironomid having blood-red larvee. Another 
point worthy of special remark is the resting position of the 
adult fly, the front legs being held in a peculiar manner 
which I have not observed in any other Chironomid. The 
front femora are directed straight forwards, so that their 
clubbed tips almost or quite touch in front of the head ; the 
tibiz and tarsi are bent right back at an angle of about 40° 
with the body. A somewhat similar posture is adopted by 
scme small species of Yanytarsus, which hold their front 
tibiz and tarsi at right angles to the body; but I do not 
now of another instance in the Chironomine in which the 
normal manner of holding the front legs is departed from, 
* Miall and Hammond, in their monograph on the ‘ Harlequin-fly ’ 
(p. 139), note that “ occasionally the larval skin is still adherent to the 
pupa when the fly emerges.” 
