410 Transactions of the Society. 



and in all I found this tube ; I could then say with certainty that 

 though the earwigs might damage our dahlias, they certainly 

 helped our roses. Another earwig is full of debris, and scales of 

 Lepidoptera can be recognised. 



The food of the mandibulate insects is comparatively easy to 

 identify, as the prey is broken up into large fragments, recognisable 

 by comparison or experience. Before describing my observations 

 of Diptera, I shall make some discursive remarks on a few other 

 Orders. In all these insects the food is in various stages of 

 digestion ; the last stage seems marked by the presence of a black, 

 finely -granular mass (occasionly only traces) in the abdomen, 

 staining the intestine, and in some cases, the mouth. This colour 

 is possibly a chemical reaction of the digestive fluids, with the 

 various chemicals through which the preparation has been passed. 

 I think, from my observations on this point, that it is highly 

 probable that the process of digestion in all insects, whatever the 

 nature of the food, is identical. 



Remarks on Various Mandibulate Insects. 



A mole cricket, Gryllotalpa americana, that came flying at the 

 lights in a hotel at Cairns, North Queensland, has the abdomen 

 full of shreds of neatly bitten vegetable, probably grass. 



The larvffi of Myrmeleon, which had made their sandy traps on 

 the borders of the Burdeken river, in the same part of Australia, 

 show reddish masses, which our knowledge of the food of these 

 creatures enables me to say is probably the digested blood or juice 

 of insects. 



In the Coleoptera, I am able to say that Pterostichus cupreus 

 was decidedly carnivorous, as I found six antennae of a Neuropteron, 

 probably a Sialid, in its stomach. 



One of the smaller water-beetles of genus Rhantus has half the 

 head of a fly in the thorax, just before the gizzard, which I recognise as 

 that of a Chironomus. That Scolopendra (centipede) is carnivorous 

 is known, and I have a specimen which contains the antenna of a 

 Coleopterous insect, probably one of the clavicorn beetles. 



Cockroaches {Periplaneta orientalis L.), are, I believe, supposed 

 to keep houses clear of other insect pests. I have a preparation of 

 a female which has the remains of other cockroaches inside. 

 These can be recognised by the peculiar sculpturing of the chitin, 

 though broken up into minute pieces. This insect was one of a 

 number kept in a trap all night. The person who caught them 

 remarked that by the morning all the small ones had disappeared. 



Of the Hymenoptera, a saw-fly {Nematus $ ) has the black 

 stain alluded to as characteristic of the last stage of digestion. 



A worker bee {Apis mellifica L.), of the Ligurian variety, had 

 the abdomen full of several species of pollen. 



