20 



SCIENCE-GOSSIP. 



[Jan. 1, 1866. 



clusters under pear-tree leaves, and cabbage leaves. 

 Sometimes they rise in a crowd from the shaken 

 branch or leaf, and settle again as mere dots upon 

 the neighbouring plants. They multiply with great 

 rapidity ; one moth will produce 200,000 aleyrodes 

 in twelve generations. Their transformations are 

 very interesting and curious. The little group of eggs 

 is so small that they appear as a mere film of white 

 powder on the leaf. The lava is a flat semi-trans- 

 parent scale upon the surface of the stem or leaf, 

 having a folded hair-like proboscis, with which it 

 pierces the plant, and sucks its juices, doing con- 

 siderable injury thereby. The pupa case which is 

 mounted with the perfect insect is like a fairy slip- 

 per, fringed with golden dots, or seemiugly set with 

 topaz on silver stems ; it is open at the top, where 

 the aleyrodes emerged after its brief trance. The 

 moth, which is not a moth, is worth minute examin- 

 ation. When first I saw this pretty little creature, I 

 thought it was the moth of a leaf-roller or leaf- 

 miner (this was in the early days of my study in 

 natural history), but placing it under the microscope, 

 the wings were not those of a lepidoptera ; they had 

 no scales or feathers, were covered with a white 

 mealy dust; it had no long proboscis, and only a 

 short antennae ; the eyes were divided into two sets, 

 on each side ; the joints of the feet only two ; and 

 from all these signs it could not be a moth. Then I 

 supposed it to be a coccus ; but, further examina- 

 tion proved this to be not so, although the relation- 

 ship is very near. The coccus in the winged state 

 has only two wings, the aleyrodes has four. The 

 coccus has only one joint in its feet, and this insect 

 has two. Also, both male and female aleyroids are 

 winged, whereas the female coccus always remains 

 in a scale-like, quiescent state. The aleyrodes rank 

 amongst the Homoptera or tribe which comprises the 

 green-fly or Apis, the musical Cicada, the strange 

 foreign Lanthorn Ely (Fulgora) and the coccus ; but 

 is in the border-land between the Lepidoptera and 

 the Aphides, a connecting link which renders this 

 preparation particularly interesting. — L. Lane 

 Clarke. 



How to Mount the Proboscis of the Blow- 

 fly. — The spreading and mounting of the proboscis 

 of the blow-fly is a process which depends for suc- 

 cess entirely upon the dexterity and practice of the 

 operator. The head must be taken fresh from the 

 insect, and gently pinched with the finger and 

 thumb between the eyes. The fluids will cause the 

 proboscis to swell, and now is the time adroitly to 

 apply a glass slide, and get the trunk somewhat into 

 position; then, without relaxing the pressure, 

 another glass slip must be gently placed over the 

 expanded proboscis, and the whole put by to dry. 

 When this is accomplished, the operator must return 

 to the attack, and moisten the specimen with clean 



water. Now arrange the brushes in their proper 

 places with the needlepoints, and after placing the 

 glass slip over the trunk for the second time, put 

 aside. An American clip may be used to keep the 

 glasses in close proximity, when the whole has been 

 finally arranged. If too great pressure be em- 

 ployed, either in pinching the head, or placing the 

 glasses in the first part of the process, the delicate 

 tissues will be ruptured, and all the labour thrown 

 away. When the mounter is satisfied that the 

 specimen is perfectly dry, he must then, with a sharp 

 microscopic knife, remove the head from the pro- 

 boscis by a clean cut. The head is by no means to 

 be squeezed by the glasses like the proboscis, but 

 must be kept outside their edges. All he has to do 

 now, is to saturate the object with turpentine, and 

 mount in balsam in the usual manner. In the 

 preparation, frequent recourse must be had to a lens, 

 as the task is a difficult one, needing plenty of care 

 and patience. One of the best of Topping's beau- 

 tiful slides of this object should be taken as a 

 standard. 1 have seen the proboscis of the blow-fly 

 prepared after a different plan. I think as follows : 

 The extreme end of the trunk is cut off with flue 

 scissors, and mounted in glycerine, so as to show 

 the spirals as nearly as possible in the natural state. 

 The former mode, though undoubtedly the most 

 effective, hardly gives a true notion of the relative 

 position of the parts. I am not aware that particular 

 instructions are given in any book relative to the 

 preparation of this subject, and I do not know what 

 may be Topping's plan. The above directions are 

 the result of an accidental discovery after many 

 vexatious failures. Bxperientia docet.—S. M'liitire. 



How to Mount the Proboscis of the Blow- 

 fly. — In answer to your querist, " T. S.," as to a 

 method of preparing and mounting the tongues of 

 flies, I beg to send the following, which I have found 

 to give good results. Sever the head from the 

 thorax, and gently squeeze it between the thumb and 

 forefinger, when the tongue will be projected out ; 

 soak the whole for two or three days in liquor 

 potasssc, and well wash it in clean water ; lay the 

 head flat on a slide, and then with a needle and fine 

 camel-hair brush arrange the various parts. Place 

 another slide gently on the tongue so as not to dis- 

 arrange it, and submit the whole to pressure in a 

 clip until dry. The tongue may then be cut from 

 the head with fine scissors, soaked for about forty- 

 eight hours in turpentine, and mounted in balsam. 

 Too long steeping in turpentine bleaches too much. 

 I may as well state that I have a dozen or so 

 mounted specimens of the tongue and lancets of the 

 drone-fly, which I shall be happy to exchange for 

 other well-mounted objects, or will forward a slide, 

 post free, to any address on receipt of ten postage 

 stamps. — William Fredk. Rogers. 



