204 THE JOURNAL OF BOTANY 



immediately to ascertain what was known on this point, but he found 

 at once that, though a certain amount of information as to ths 

 tongue-lengths of a few of the commoner humble-bees, bee-flies, and 

 butterflies was given by Muller {Fertilization of Flowers by Insects^ 

 1883) and Knath {Flower Pollination, 190o-09) in their well-known 

 works on flower-pjllination, nothing was recorded as to the tongue- 

 lengths of thi night- fljdng moths likolj to be concerned in the 

 pollination of the Primrose — nor, indeed, of any other of our spring- 

 flowering plants. 



In this dilemma, Mr. Christ}^ (having sought help, without 

 success, from all the entomologists of his acquaintance, including 

 Dr. Perkins) called at the Entomological Department of the British 

 Museum to inquire whether anything was known as to the tongue- 

 lengths of the various moths on Dr. Perkins's list. The matter was 

 (as Mr. Christy painted out) of some impjrtance to botanists, 

 agriculturists, horticulturists, and others, in connection with the 

 pollination of flowers and the consequent production of good and 

 fertile seed. 



However, the information he sought was not available, inasmuch 

 as the subject of tougue-lengths had been neglected almost entirely, 

 both by insect-collectors and entomologists: the chief reason being 

 that, to them, the subject was of little or no interest, inasmuch as 

 the length of tongue (being in many species, at least, highly variable) 

 could not be depended upon as a specific character. It w^as then sug- 

 gested to me that it might be of use if I measured the tongue-lengths 

 of the various moths on Dr. Perkins's list — and this I did. 



The task might have been easy if fresh specimens had been 

 availalde to Avork on ; but it was by no means easy in view of the 

 fact that I w^as obliged to make use of the old duplicate specimens in 

 the Museum cabinets. It may be useful to others desiring to make 

 similar investigations to explain the metliod adopted : — The heads of 

 the moths were soaked for 24 hours in KOH (10 percent.). In some 

 cases the proboscis unrolled as a result of the softening, in the otlier 

 eases it was unnecessary to unroll it. A piece of celluloid, marked 

 with millimetres, was then placed in the bottom of an inverted watch- 

 glass containing alcohol and, so far as possible, the proboscis 

 straightened out along the scale. It was thus possible to estimate 

 its length approximately, allowing for the fact that it was not 

 possible absolutely to straighten the proboscis. 



The results are set forth in the Table (p. 205), which shows also 

 the months during which each species of insect flies and the chief 

 flowers it is known to visit (this information is taken mainly from 

 Mr. A. Gr. Scorer's Fntomologisfs Log-Book, 1912). 



When these results were submitted to Mr. Christy, Ke found that 

 four only of the species examined (namely, Calocampa exoleta, 

 C vetttsta, Cucullia verhasei, and Fhlogophora meticulosa) had 

 tongues long enough to render them of interest in connection with 

 his investigations, but that those four were of special interest, 

 inasmuch as all of them are (like the Primrose) abundant throughout 

 the whole of the British Isles and one of them (T. verhasci) is the 



