TTM® m^mmmicmn mmm j©i3;i«N»iL. 



535 



their larval existence. The drone 

 larva; receive a considerable addition 

 of undigested pollen in the second 

 period, whereas the queen and worker 

 larvaj h-vve none but what is digested 

 in the cliyle stomach. Both drone and 

 worker larva; have a large addition of 

 honey to their food in the second 

 period, whereas the queen larva has 

 no difl'erence made in her food. The 

 food is produced in the chyle stomach 

 from honey and pollen consumed. 



In a letter to me from Dr. dePlanta, 

 asking for some explanations, he says 

 that two things must first be separated 

 — (1) pollen as found in nature, and 

 which is easily detected by the micro- 

 scope ; and (2) pollen which has been 

 digested in the stomach, as with us 

 meat, cheese, etc. In this last form, 

 invisible yet present, it forms with 

 honey the food of the queen larvfe, and 

 that of the first period of the drone 

 and worker larvse. The worker larva; 

 get a larger proportion of albumen 

 than even the queen, and Dr. Planta 

 considers it is because of the small 

 size of the cells, and the small quantity 

 of food administered to them by the 

 nurses necessitating a more nourish- 

 ing form of food for their development. 

 The drones are therefoi-e weaned from 

 the fourth day, by the addition of nat- 

 ural pollen in an undigested state. 

 The worker larviB are also weaned, 

 but in a diflerent manner, for instead 

 of having undigested pollen given 

 them thej' continue to be fed on 

 digested food, with the addition of 

 honey oulj'. 



Under the microscope at no stage of 

 development of the queen or worker 

 larvse was any free pollen found, nor 

 any skins. Dr. Planta repeated the 

 experiment over and over again with 

 the same result, and those who have 

 stated that worker larva; are weaned 

 by having undigested pollen added to 

 their food in the second period of their 

 existence have erred, or have repeated 

 Leuckart's error. 



Very different is it with the drone 

 larviB. After the fourth da}% a large 

 amount of pollen in an undigested 

 state was found. Prof. Kramer made 

 several microscopical examinations, 

 and found in one milligramme of 

 larval food, occupying a surface of 

 1,440 mm. square, the immense num- 

 ber of 15,000 pollen-grains. Besides 

 this it will be seen from the table that 

 a considerable quantity of sugar in the 

 shape of honey is added to the food. 

 Dr. Planta considers this method of 

 feeding the drone larvoe as a saving 

 of time to the workers. The first four 

 days they feed them liberally on rich 

 food, to rapidly develop the larvas, and 

 then, when they are strong enough, 

 they give them pollen and allow them 

 to digest this themselves, and reduce 



the quantity of digested food they give 

 them. It is easy to understand the 

 saving of time to the bees by bearing 

 in mind the large quantity of pollen 

 found in the food. 



Dr. Planta is the first who has made 

 a separate analysis of the food on dif- 

 ferent days, and of the diflerent bees, 

 and he is also the first who has liy his 

 experiments corroborated Schonfeld's 

 opinions. 



It is easy to understand how former 

 observers have gone wrong ; if all the 

 food taken from worker and drone 

 cells over four days is mixed up, of 

 course pollen will be found, and this 

 misled Leuckart and those who have 

 followed him. 



These experiments of Dr. Planta 

 show that the food of the larva; is a 

 digested food, and fully corroborate 

 Schonfeld's theories — that the bees 

 also are able, and do vary it in various 

 proportions, whereas, if it were a 

 secretion onlj', as claimed by Schie- 

 menz, it could not vary to such an ex- 

 tent. I do not wish you to understand 

 that the glands take no part in the 

 feeding, for Schonfeld, Holz, and 

 others, admit that secretions may be 

 added to the food ; but what I want to 

 impress upon you is, that they do not 

 form the actual mass of the brood 

 food, as taught by Schiemenz and his 

 school. 



The subject may not be interesting 

 to every one, but these experiments 

 have a practical bearing on bee-keep- 

 ing, more especially on queen-rearing. 

 Leuckart found that the first traces of 

 the ovaries appeared in the larva after 

 the third day of its leaving the egg, 

 and this is just the period at which the 

 change of food takes place. In the 

 larva intended for a queen, the rich 

 food is continued abundantl}' to the 

 last, and this has the efl'ect of fully 

 developing the ovaries. On the con- 

 trar)', the change of food in the worker 

 larva stops this development. If, there- 

 fore, we want good queens, we must 

 see that we rear them from larvte that 

 have been abundantly fed on the rich 

 nitrogenous food from the commence- 

 ment of their existence. 



There are other aspects of the ques- 

 tion, but I have not the time to enter 

 into them ; I think I have said enough 

 to make you see the value of this work. 

 The question of brood food, I think, is 

 now definitely settled, and we may 

 take it for granted that it is produced 

 in the cliyle stomach, and ejected bj' 

 the mechanism I have described. 



The delivery of the foregoing ad- 

 dress by Mr. Cowan, was followed by 

 this interesting discussion of the sub- 

 ject under consideration : 



Mr. Grimshaw said he felt sure they 

 would all feel grateful to Mr. Cowan 



for hi.s excellent address. .Speaking 

 for himself, however, he felt pained 

 becau.sc Mr. Cowan had shak(;n to its 

 foundation one of his (the speaker's) 

 pet beliefs. He (Mr. Grimshaw) agreed 

 that the food given to worker larva; 

 was a production of the chyle stomach, 

 and was, so to speak, pumped back 

 again, but lu; could not but think that 

 the highly-charged nitrogenous ma- 

 terial which the queen larva; fed upon 

 was so entirely different from the food 

 Mr. Cowan had told them about as 

 prepared in the chyle stomach, that it 

 must be evolved by some separate 

 process. There were four sets of 

 glands, and he would ask what were 

 the uses of them if not to provide the 

 highly nitrogenous food the queen was 

 fed upon ? Mr. Cowan said for de- 

 glutition and assimilation, but that was 

 not suflicier.t ; and until a proper use 

 for these glands was found other than 

 the one hitherto supposed, he must 

 cling to the old theory. At any rate, 

 the analysis of the various foods was 

 so startling that he was bonnd to give 

 the matter serious thought, and ex- 

 press his opinions with great deference 

 to the quoted authorities. 



Mr. Cowan said that Schiemenz 

 supposed all the glands to take part in 

 the production of the brood food, al- 

 though No. 1, he said, was the princi- 

 pal source ; but Schonfeld did not hold 

 that view. In the first place, the 

 glands were very small in proportion 

 to the quantit}' of the food — in fact, 

 too small to be able to secrete the im- 

 mense amount of food that was neces- 

 sary, to say nothing about its variation 

 in the diflerent larvos. 



Mr. Grimshaw believed thatheredity 

 among bees was carried down by 

 means of brood food, and it was nec- 

 essary for his argument that the food 

 given to the brood should pass through 

 the .system of the nurse-bee in order 

 that heredity might lie transmitted. 



He held that the instincts, which the 

 worker-bees had, could only be handed 

 down from worker to worker l>3' food 

 passed tl'rough the system and given 

 to the brood ; that such food was a 

 secretion of one or two special glands, 

 bnt that the rich nitrogenous food was 

 a distinct mammary secretion. The 

 estaldishment of Mr. Cowan's theory 

 would totally upset his (the sijeaker's) 

 view of heredit)'. 



Mr. Lyon understood Mr. Cowan to 

 say that there was an absence of pol- 

 len remains in the food supplied to 

 bees up to the third day. If so. that 

 would support Mr. Grimshaw's theory 

 oif secretion. After the third day the 

 secretion was discontinued, and the 

 semi-digested chyle pumped through 

 the oesophagus into the cells for brood 

 nourishment. 



