A METHOD OF PHOTOGRAPHING LEPIDOPTEROUS OVA. Ill 



A method of photographing lepidopterous ova {mth plate). 



By A. E. TONGE. 



It is comparatively quite a short time ago since I found a batch of 

 ova of a lepidopterous insect on a blackthorn twig, and was much sur- 

 prised to discover what a difficult matter the accurate identification of 

 the species proved to be. I know now that it was quite a common 

 one, but the incident served to show how very little is known about 

 the ova of our moths and butterflies, even by those to whom their 

 subsequent life-history is quite familiar, and, as a result, I hit upon 

 the idea of bringing photography, of which 1 had some slight previous 

 experience, to my aid, in order to throw some light on this apparently 

 obscure department of entomological science. The outcome of this 

 has been many hours of most pleasurable and interesting work for 

 myself, and I trust that the photographs which have been published 

 in Part III of Practical Hints for the Field Lepiihipterist, one plate of 

 which was reproduced in the Kntoni. Record for February last, and 

 the brief account of my method of working, which Mr. Tutt was good 

 enough to ask me to contribute for this most useful publication, have 

 not been without interest to others. 



It may, therefore, not be out of place here to express my thanks to 

 those many friends who have so kindly lent me ova of various species 

 from time to time in order that I might photograph them, and to 

 hope that they and others will continue similar help in future, as I 

 have only been able to do a comparatively small portion of the British 

 lepidoptera as yet, owing to the limited amount of leisure time at my 

 disposal. I particularly want help with ova of the British " Plume " 

 moths of all species, for reproduction in the next volume of British 

 Lepidoptera, upon which Mr. J. W. Tutt, Dr. T. A. Chapman, and 

 Mr. A. W. Bacot are at present engaged. 



My first attempts at photographing ova were made with an ordinary 

 ^-plate stand camera, focussing from the back, attached to a student's 

 microscope, and with this I was able to obtain results which surprised 

 me, but was handicapped by the short extension obtainable with the 

 camera (about 15in.), as this necessitated using the eyepiece of the 

 microscope to bring the image to a focus at a point nearer the objec- 

 tive than would otherwise be necessary. This caused some loss in 

 definition, and I also had considerable difficulty in getting an objective 

 of long enough focus to cover the whole of a small batch of ova and at 

 the same time admit of the object being focussed with the eyepiece I 

 possessed. Having obtained a Sin. objective which filled these neces- 

 sary requirements, the next step was to construct a base board on 

 which to fix the camera and microscope in proper alignment. For 

 this purpose I used a smooth deal board about 3ft. long. Gin. wide, 

 and lin. thick, and ruled a straight line down the centre from end to 

 end as a guide to oi^taining a proper alignment of the comialeted 

 apparatus. On placing the camera and microscope upon it, with the 

 body tube of the latter lowered to a horizontal position, I found that 

 the line of projection was considerably below the lens aperture in the 

 camera front, so the next step was to construct a block for the micro- 

 scope to stand upon, which would raise it sufficiently to bring the 

 eyepiece exactly in the centre of the lens aperture, and permit of an 

 imaginary line being drawn horizontally from the centre of the 

 May 15th, 1905. 



