182 



Proceedings. 



[No. 9, NEW SERIES. 



Lieut. Mitchell exhibits 18 Micro-photographs, and at the re- 

 quest of the President, has given the following description of them. 



No. 1. — The Parasite of a Goose. This is a member of the 

 order " Anoplura" to which belongs the common louse ; it is thus 

 characterized. 



" Feet six ; wings none ; parasitic, and not undergoing meta- 

 morphosis ; eyes two, simple, or none. 



" The order is divided into two sub-orders, the first termed 

 Haustellata, has a mouth with a tubular very short haustellum. 



The second sub-order has a mandibulate mouth placed under- 

 neath the head, there are five joints in the antennse, and a double 

 claw to each foot in the Genus Philopterus, to which we believe 

 the subject of our Photograph belongs. 



Nos. 2 and 8. — Represent the proboscis of the Blow-fly. The 

 two fleshy lobes of which are kept in a state of expansion, at the 

 will of the insect, by means of the beautiful series of tubes seen 

 in the Photograph and termed modified trachea, this is a very 

 beautiful object for the microscope, and may be very well seen 

 with a good objective of 1 inch focus, but higher powers are re- 

 quired to display the ultimate structure of the tracheal tubes. 



No. 3. — The parasite of the common domestic Fowl. 



This is an acarus and belongs to the same genus as the cheese 

 mite. It has eight legs, each of which terminates in a double 

 claw and has an acetabulum or sucker. The head is said to be 

 furnished* with two large mandibles, these consist of a soft re- 

 tractile basal joint, and a second dilated non-retractile joint resem- 

 bling the fixed claw of a Lobster, and a moveable piece working 

 against the latter, the two last pieces are toothed where in contact 

 with each other ; these mandibles can be advanced either sepa- 

 rately or together, and can be separated or approximated." 



No. 4. — A Butterfly's scale. This is a representation of one of 

 the minute particles of dust that adheres to the fingers when a 

 Butterfly is caught. The wing of a Butterfly consists of a deli- 

 cate framework of nervures or veins, enclosed between two trans- 

 parent membranes of great tenuity. To these membranes the 

 scales are attached by the small pedicle or stalk, which fits into a 



• Micro-graphical Dictionary. 



